Question: How many years was it between World War 1 and World War 2?

Interwar period





In the context of the history of the 20th century, the interwar period was the period between the end of the First World War in November 1918 and the beginning of the Second World War in September 1939.
Despite the relatively short period of time, this period represented an era of significant changes worldwide. Petroleum and associated mechanisation expanded dramatically leading to the Roaring Twenties (and the Golden Twenties), a period of economic prosperity and growth for the middle class in North America, Europe and many other parts of the world. Automobiles, electric lighting, radio broadcasts and more became commonplace among populations in the developed world. The indulgences of this era subsequently were followed by the Great Depression, an unprecedented worldwide economic downturn which severely damaged many of the world's largest economies.
Politically, this era coincided with the rise of communism, starting in Russia with the October Revolution, at the end of World War I, and ended with the rise of fascism, particularly in Germany and in Italy. China was in the midst of long period of instability and civil war between the Kuomintang and the Communist Party of China. The Empires of Britain, France and others faced challenges as imperialism was increasingly viewed negatively in Europe, and independence movements in British India, French Indochina, Ireland and other regions gained momentum. 
The Ottoman, Austro-Hungarian and German empires were dismantled. The Ottoman and German Empire's colonies were redistributed among the Allies. The far western part of the Russian Empire broke away: Estonia, Finland, Latvia, Lithuania and Poland became independent nations, while Bessarabia (the Republic of Moldova) chose to reunify with Romania. 
The communists in the USSR managed to regain control in Ukraine, Armenia, Azerbaijan and Georgia. Ireland was split, with the larger part being independent of Britain. In the Middle East, Egypt and Iraq gained independence. During the Great Depression, Latin American countries nationalised many foreign companies (particularly American) in a bid to strengthen their local economies. Japanese, German, Italian and Soviet territorial ambitions led to expansions of these empires, which set the stage for the subsequent world war.
The German and Soviet invasion of Poland in September 1939 is considered the start of World War II and the end of the interwar period.[1]
Turmoil in Europe

Following the Armistice of 11 November 1918 that ended World War I, the years 1919–24 were marked by turmoil as affected regions struggled to recover from the devastation of the First World War and the destabilising effects of the loss of four large historic empires: the German Empire, Austro-Hungarian Empire, Russian Empire and the Ottoman Empire. There were numerous new nations in Eastern Europe, most of them small in size. The United States gained dominance in world finance. Thus, when Germany could no longer afford war reparations to Britain, France and other Allies, the Americans came up with the Dawes Plan and Wall Street invested heavily in Germany, which repaid its reparations to nations that, in turn, used the dollars to pay off their war debts to Washington. By the middle of the decade, prosperity was widespread, with the second half of the decade known, especially in Germany, as the "Golden Twenties".[2]
International relations

The important stages of interwar diplomacy and international relations included resolutions of wartime issues, such as reparations owed by Germany and boundaries; American involvement in European finances and disarmament projects; the expectations and failures of the League of Nations;[3] the relationships of the new countries to the old; the distrustful relations of the Soviet Union to the capitalist world; peace and disarmament efforts; responses to the Great Depression starting in 1929; the collapse of world trade; the collapse of democratic regimes one by one; the growth of efforts at economic autarky; Japanese aggressiveness toward China, occupying most of China's Pacific coastline, as well as border disputes between the Soviet Union and Japanese Empire, leading to multiple clashes along the Soviet and Japanese occupied Manchurian border; Fascist diplomacy, including the aggressive moves by Mussolini's Italy and Hitler's Germany; the Spanish Civil War; Italy's invasion and occupation of Abyssinia (Ethiopia) in the Horn of Africa; the appeasement of Germany's expansionist moves against the German-speaking nation of Austria, the region inhabitanted by ethnic Germans called the Sudetenland in Czechoslovakia, the remilitarization of the Legue of Nations demilitarized zone of the German Rhineland region, and the last, desperate stages of rearmament as the Second World War increasingly loomed.[4]
Disarmament was high on the popular agenda. The League of Nations played little role in this effort, but the United States and Britain took the lead. U.S. Secretary of State Charles Evans Hughes sponsored the Washington Naval Conference of 1921 in determining how many capital ships each major country was allowed.  The new allocations were actually followed and there were no naval races in the 1920s.  Britain played a leading role in the 1927 Geneva Naval Conference and the  1930 London Conference that led to the London Naval Treaty, which added cruisers and submarines to the list of ship allocations. However the refusal of Japan, Germany, Italy and the USSR to go along with this led to the meaningless Second London Naval Treaty of 1936.  Naval disarmament had collapsed and the issue became rearming for a war against Germany and Japan.[5][6]
Roaring Twenties

The "Roaring Twenties" highlighted novel and highly visible social and cultural trends and innovations. These trends, made possible by sustained economic prosperity, were most visible in major cities like New York, Chicago, Paris, Berlin, and London. The Jazz Age began and Art Deco peaked.[7][8] For women, knee-length skirts and dresses became socially acceptable, as did bobbed hair with a marcel wave. The young women who pioneered these trends were called "flappers".[9] Not all was new: “normalcy” returned to politics in the wake of hyper-emotional wartime passions in the United States, France, and Germany.[10] The leftist revolutions in Finland, Poland, Germany, Austria, Hungary, and Spain were defeated by conservatives, but succeeded in Russia, which became the base for Soviet Communism.[11] In Italy the fascists came to power under Mussolini after threatening a March on Rome in 1922.[12]
Most independent countries enacted women's suffrage in the interwar era, including Canada in 1917 (though Quebec held out longer), Britain in 1918, and the United States in 1920. There were a few major countries that held out until after the Second World War (such as France, Switzerland and Portugal).[13] Leslie Hume argues:
The women's contribution to the war effort combined with failures of the previous systems' of Government made it more difficult than hitherto to maintain that women were, both by constitution and temperament, unfit to vote. If women could work in munitions factories, it seemed both ungrateful and illogical to deny them a place in the polling booth. But the vote was much more than simply a reward for war work; the point was that women's participation in the war helped to dispel the fears that surrounded women's entry into the public arena.[14]
In Europe, according to Derek Aldcroft and Steven Morewood, "Nearly all countries registered some economic progress in the 1920s and most of them managed to regain or surpass their pre-war income and production levels by the end of the decade." The Netherlands, Norway, Sweden, Switzerland, and Greece did especially well, while Eastern Europe did poorly.[15] In advanced economies the prosperity reached middle class households and many in the working class. with radio, automobiles, telephones, and electric lighting and appliances. There was unprecedented industrial growth, accelerated consumer demand and aspirations, and significant changes in lifestyle and culture. The media began to focus on celebrities, especially sports heroes and movie stars. Major cities built large sports stadiums for the fans, in addition to palatial cinemas. The mechanization of agriculture continued apace, producing on expansion of output that lowered prices, and made many farm workers redundant. Often they moved to nearby industrial towns and cities.
Great Depression
The Great Depression was a severe worldwide economic depression that took place after 1929. The timing varied across nations; in most countries it started in 1929 and lasted until the late 1930s.[16] It was the longest, deepest, and most widespread depression of the 20th century.[17] The depression originated in the United States and became worldwide news with the stock market crash of October 29, 1929 (known as Black Tuesday). Between 1929 and 1932, worldwide GDP fell by an estimated 15%. By comparison, worldwide GDP fell by less than 1% from 2008 to 2009 during the Great Recession.[18] Some economies started to recover by the mid-1930s. However, in many countries, the negative effects of the Great Depression lasted until the beginning of World War II.[19]
The Great Depression had devastating effects in countries both rich and poor. Personal income, tax revenue, profits, and prices dropped, while international trade plunged by more than 50%. Unemployment in the U.S. rose to 25% and in some countries rose as high as 33%.[20] Prices fell sharply, especially for mining and agricultural commodities. Business profits fell sharply as well, with a sharp reduction in new business starts.
Cities all around the world were hit hard, especially those dependent on heavy industry. Construction was virtually halted in many countries. Farming communities and rural areas suffered as crop prices fell by about 60%.[21][22][23] Facing plummeting demand with few alternative sources of jobs, areas dependent on primary sector industries such as mining and logging suffered the most.[24]
The Weimar Republic in Germany gave way to two episodes of political and economic turmoil, the first culminated in the German hyperinflation of 1923 and the failed Beer Hall Putsch of that same year. The second convulsion, brought on by the worldwide depression and Germany's disastrous monetary policies, resulted in the further rise of Nazism.[25] In Asia, Japan became an ever more assertive power, especially with regard to China.[26]
Fascism displaces democracy
Democracy and prosperity largely went together in the 1920s. Economic disaster led to a distrust in the effectiveness of democracy and its collapse in much of Europe, including the Baltic and Balkan countries, Poland, Spain, and Portugal. Powerful expansionary dictatorships emerged in Italy, Japan, and Germany.[27]
While communism was tightly contained in the isolated Soviet Union, fascism took control of Italy in 1922; as the Great Depression worsened, fascism emerged victorious in Germany, and played a major role in numerous countries in Europe, and several in Latin America.[28] Fascist parties sprang up, attuned to local right-wing traditions, but also possessing common features that typically included extreme militaristic nationalism, a desire for economic self-containment, threats and aggression toward neighboring countries, oppression of minorities, a ridicule of democracy while using its techniques to mobilize an angry middle-class base, and a disgust with cultural liberalism. Fascists believed in power, violence, male superiority, and a "natural" hierarchy, often led by dictators such as Benito Mussolini or Adolf Hitler. Fascism in power meant that liberalism and human rights were discarded, and individual pursuits and values were subordinated to what the party decided was best.[29]
Spanish Civil War (1936–39)

To one degree or another, Spain had been unstable politically for centuries, and in 1936-39 was wracked by one of the bloodiest civil wars of the 20th century. The real importance comes from outside countries.  In Spain the conservative and Catholic elements, and the army, in Spain revolted against the newly elected government, and full-scale civil war erupted.  Fascist Italy and Nazi Germany gave munitions and strong military units to the rebel Nationalists, led by General Francisco Franco. The Republican (or "Loyalist") government, was on the defensive, but it received significant help from the Soviet Union. Led by Great Britain and France, and including the United States, most countries remained neutral and refused to provide armaments to either side. The powerful fear was that this localized conflict would escalate into a European conflagration that no one wanted. [30][31]
The Spanish Civil War was marked by numerous small battles and sieges, and many atrocities, until the Nationalists won in 1939 by overwhelming the Republican forces. The Soviet Union provided armaments  but never enough to equip the heterogeneous government militias and the  "International Brigades" of outside far-left volunteers. The civil war did not escalate into a larger conflict, but did become a worldwide ideological battleground that pitted all the Communists and many socialists and liberals against Catholics, conservatives and fascists.  Worldwide there was a decline in pacifism and a growing sense that another great war was imminent, and that it would be worth fighting for.[32][33]
Great Britain and its Empire


The changing world order that the war had brought about, in particular the growth of the United States and Japan as naval powers, and the rise of independence movements in India and Ireland, caused a major reassessment of British imperial policy.[34] Forced to choose between alignment with the United States or Japan, Britain opted not to renew its Japanese alliance and instead signed the 1922 Washington Naval Treaty, where Britain accepted naval parity with the United States. The issue of the empire's security was a serious concern in Britain, as it was vital to the British pride, its finance, and its trade-oriented economy.[35][36]

India strongly supported the Empire in the First World War. It expected a reward, but failed to get home rule as the Raj kept control in British hands and feared another rebellion like that of 1857. The Government of India Act 1919 failed to satisfy demand for independence. Mounting tension, particularly in the Punjab region, culminated in the Amritsar Massacre in 1919. Nationalism surged and centered in the Congress Party led by Mohandas Gandhi.[37] In Britain public opinion was divided over the morality of the massacre, between those who saw it as having saved India from anarchy, and those who viewed it with revulsion.[38][39]
Egypt had been under de facto British control since the 1880s, despite its nominal ownership by the Ottoman Empire. In 1922 it was granted formal independence, though it continued to be a client state following British guidance. Egypt joined the League of Nations. Egypt's King Faud and his son King Farouk, and their conservative allies, stayed in power with lavish lifestyles thanks to an informal alliance with Britain who would protect them from both secular and Muslim radicalism.[40] Iraq, a British mandate since 1920, gained official independence in 1932 when King Faisal agreed to British terms of a military alliance and an assured flow of oil.[41][42]
In Palestine, Britain was presented with the problem of mediating between the Arabs and increasing numbers of Jews. The 1917 Balfour Declaration, which had been incorporated into the terms of the mandate, stated that a national home for the Jewish people would be established in Palestine, and Jewish immigration allowed up to a limit that would be determined by the mandatory power. This led to increasing conflict with the Arab population, who openly revolted in 1936. As the threat of war with Germany increased during the 1930s, Britain judged the support of Arabs as more important than the establishment of a Jewish homeland, and shifted to a pro-Arab stance, limiting Jewish immigration and in turn triggering a Jewish insurgency.[43]
The Dominions (Canada, Newfoundland, Australia, New Zealand, South Africa and Ireland) were self-governing and gained semi-independence in the World War. Britain still controlled foreign policy and defence. The right of the Dominions to set their own foreign policy was recognised in 1923 and formalised by the 1931 Statute of Westminster. Ireland effectively broke all ties with London in 1937.[44]
French Empire


French census statistics from 1931 show an imperial population, outside of France itself, of 64.3 million people living on 11.9 million square kilometers. Of the total population, 39.1 million lived in Africa and 24.5 million lived in Asia; 700,000 lived in the Caribbean area or islands in the South Pacific. The largest colonies were Indochina with 21.5 million (in five separate colonies), Algeria with 6.6 million, Morocco, with 5.4 million, and West Africa with 14.6 million in nine colonies. The total includes 1.9 million Europeans, and 350,000 "assimilated" natives.[45]
Revolt in North Africa Against Spain and France

The Berber independence leader Abd el-Krim (1882-1963) organized armed resistance against the Spanish and French for control of Morocco. The Spanish had faced unrest off and on from the 1890s, but in 1921 Spanish forces were massacred at the Battle of Annual El-Krim founded an independent Rif Republic  that operated until 1926 but had no international recognition. Paris and Madrid agreed to collaborate to destroy it. They sent in 200,000 soldiers, forcing el-Krim to surrender in 1926; he was exiled in the Pacific until 1947.  Morocco became quiet, and in 1936 became the base from which Francisco Franco launched his revolt against Madrid.[46]
Germany

Weimar Republic
The humiliating peace terms in the Treaty of Versailles provoked bitter indignation throughout Germany, and seriously weakened the new democratic regime. The Treaty stripped Germany of all of its overseas colonies, of Alsace and Lorraine, and of predominantly Polish districts. The Allied armies occupied industrial sectors in western Germany including the Rhineland, and Germany was not allowed to have a real army, navy, or air force. Reparations were demanded, especially by France, involving shipments of raw materials, as well as annual payments.[47]
When Germany defaulted on its reparation payments, French and Belgian troops occupied the heavily industrialised Ruhr district (January 1923). The German government encouraged the population of the Ruhr to passive resistance: shops would not sell goods to the foreign soldiers, coal mines would not dig for the foreign troops, trams in which members of the occupation army had taken seat would be left abandoned in the middle of the street. The German government printed vast quantities of paper money, causing hyperinflation, which also damaged the French economy.  The passive resistance proved effective, insofar as the occupation became a loss-making deal for the French government. But the hyperinflation caused many prudent savers to lose all the money they had saved. Weimar added new internal enemies every year, as anti-democratic Nazis, Nationalists, and Communists battled each other in the streets. See 1920s German inflation.[48]
Germany was the first state to establish diplomatic relations with the new Soviet Union. Under the Treaty of Rapallo, Germany accorded the Soviet Union de jure recognition, and the two signatories mutually cancelled all pre-war debts and renounced war claims.  In October 1925 the Treaty of Locarno was signed by Germany, France, Belgium, Britain, and Italy; it recognised Germany's borders with France and Belgium. Moreover, Britain, Italy, and Belgium undertook to assist France in the case that German troops marched into the demilitarised Rhineland. Locarno paved the way for Germany's admission to the League of Nations in 1926.[49]
Nazi era, 1933–39

Hitler came to power in January 1933, and inaugurated an aggressive power designed to give Germany economic and political domination across central Europe.  He did not attempt to recover the lost colonies.  Until August 1939, the Nazis denounced Communists and the Soviet Union as the greatest enemy, along with the Jews.[50]

Hitler's diplomatic strategy in the 1930s was to make seemingly reasonable demands, threatening war if they were not met. When opponents tried to appease him, he accepted the gains that were offered, then went to the next target. That aggressive strategy worked as Germany pulled out of the League of Nations (1933), rejected the Versailles Treaty, and began to re-arm (1935), won back the Saar (1935), remilitarized the Rhineland (1936), formed an alliance ("axis") with Mussolini's Italy (1936), sent massive military aid to Franco in the Spanish Civil War (1936–39), seized Austria (1938), took over Czechoslovakia after the British and French appeasement of the Munich Agreement of 1938, formed a peace pact with Joseph Stalin's Soviet Union in August 1939, and finally invaded Poland in September 1939. Britain and France declared war and World War II began– somewhat sooner than the Nazis expected or were ready for.[51]
After establishing the "Rome-Berlin axis" with Benito Mussolini, and signing the Anti-Comintern Pact with Japan– which was joined by Italy a year later in 1937– Hitler felt able to take the offensive in foreign policy. On 12 March 1938, German troops marched into Austria, where an attempted Nazi coup had been unsuccessful in 1934. When Austrian-born Hitler entered Vienna, he was greeted by loud cheers. Four weeks later, 99% of Austrians voted in favour of the annexation (Anschluss) of their country Austria to the German Reich. After Austria, Hitler turned to Czechoslovakia, where the 3.5million-strong Sudeten German minority was demanding equal rights and self-government.[52][53]
At the Munich Conference of September 1938, Hitler, the Italian leader Benito Mussolini, British Prime Minister Neville Chamberlain, and French Prime Minister Édouard Daladier agreed upon the cession of Sudeten territory to the German Reich by Czechoslovakia. Hitler thereupon declared that all of German Reich's territorial claims had been fulfilled. However, hardly six months after the Munich Agreement, in March 1939, Hitler used the smoldering quarrel between Slovaks and Czechs as a pretext for taking over the rest of Czechoslovakia as the Protectorate of Bohemia and Moravia. In the same month, he secured the return of Memel from Lithuania to Germany. Chamberlain was forced to acknowledge that his policy of appeasement towards Hitler had failed.[54][55]
Italy



In 1922, the leader of the Italian fascist movement, Benito Mussolini, became Prime Minister of Italy after the March on Rome. Mussolini resolved the question of sovereignty over the Dodecanese at the 1923 Treaty of Lausanne, which formalized Italian administration of both Libya and the Dodecanese Islands, in return for a payment to Turkey, the successor state to the Ottoman Empire, though he failed in an attempt to extract a mandate of a portion of Iraq from Britain.
The month following the ratification of the Lausanne treaty, Mussolini ordered the invasion of the Greek island of Corfu after the Corfu incident. The Italian press supported the move, noting that Corfu had been a Venetian possession for four hundred years. The matter was taken by Greece to the League of Nations, where Mussolini was convinced by Britain to evacuate Italian troops, in return for reparations from Greece. The confrontation led Britain and Italy to resolve the question of Jubaland in 1924, which was merged into Italian Somaliland.[56]
During the late 1920s, imperial expansion became an increasingly favoured theme in Mussolini's speeches.[57] Amongst Mussolini's aims were that Italy had to become the dominant power in the Mediterranean that would be able to challenge France or Britain, as well as attain access to the Atlantic and Indian Oceans.[57] Mussolini alleged that Italy required uncontested access to the world's oceans and shipping lanes to ensure its national sovereignty.[58] This was elaborated on in a document he later drew up in 1939 called "The March to the Oceans", and included in the official records of a meeting of the Grand Council of Fascism.[58] This text asserted that maritime position determined a nation's independence: countries with free access to the high seas were independent; while those who lacked this, were not. Italy, which only had access to an inland sea without French and British acquiescence, was only a "semi-independent nation", and alleged to be a "prisoner in the Mediterranean":[58]
The bars of this prison are Corsica, Tunisia, Malta, and Cyprus. The guards of this prison are Gibraltar and Suez. Corsica is a pistol pointed at the heart of Italy; Tunisia at Sicily. Malta and Cyprus constitute a threat to all our positions in the eastern and western Mediterrean. Greece, Turkey, and Egypt have been ready to form a chain with Great Britain and to complete the politico-military encirclement of Italy. Thus Greece, Turkey, and Egypt must be considered vital enemies of Italy's expansion... The aim of Italian policy, which cannot have, and does not have continental objectives of a European territorial nature except Albania, is first of all to break the bars of this prison... Once the bars are broken, Italian policy can only have one motto – to march to the oceans.—Benito Mussolini, The March to the Oceans[58]

In the Balkans, the Fascist regime claimed Dalmatia and held ambitions over Albania, Slovenia, Croatia, Bosnia and Herzegovina, Vardar Macedonia, and Greece based on the precedent of previous Roman dominance in these regions.[59] Dalmatia and Slovenia were to be directly annexed into Italy while the remainder of the Balkans was to be transformed into Italian client states.[60] The regime also sought to establish protective patron-client relationships with Austria, Hungary, Romania, and Bulgaria.[59]
In both 1932 and 1935, Italy demanded a League of Nations mandate of the former German Cameroon and a free hand in Ethiopia from France in return for Italian support against Germany (see Stresa Front).[61] This was refused by French Prime Minister Édouard Herriot, who was not yet sufficiently worried about the prospect of a German resurgence.[61] The failed resolution of the Abyssinia Crisis led to the Second Italo-Ethiopian War, in which Italy annexed Ethiopia to its empire.
Italy's stance towards Spain shifted between the 1920s and the 1930s. The Fascist regime in the 1920s held deep antagonism towards Spain due to Miguel Primo de Rivera's pro-French foreign policy. In 1926, Mussolini began aiding the Catalan separatist movement, which was led by Francesc Macià, against the Spanish government.[62] With the rise of the left-wing Republican government replacing the Spanish monarchy, Spanish monarchists and fascists repeatedly approached Italy for aid in overthrowing the Republican government, in which Italy agreed to support them in order to establish a pro-Italian government in Spain.[62] In July 1936, Francisco Franco of the Nationalist faction in the Spanish Civil War requested Italian support against the ruling Republican faction, and guaranteed that, if Italy supported the Nationalists, "future relations would be more than friendly" and that Italian support "would have permitted the influence of Rome to prevail over that of Berlin in the future politics of Spain".[63] Italy intervened in the civil war with the intention of occupying the Balearic Islands and creating a client state in Spain.[64] Italy sought the control of the Balearic Islands due to its strategic position – Italy could use the islands as a base to disrupt the lines of communication between France and its North African colonies and between British Gibraltar and Malta.[65] After the victory by Franco and the Nationalists in the war, Allied intelligence was informed that Italy was pressuring Spain to permit an Italian occupation of the Balearic Islands.[66]

After the United Kingdom signed the Anglo-Italian Easter Accords in 1938, Mussolini and foreign minister Ciano issued demands for concessions in the Mediterranean by France, particularly regarding Djibouti, Tunisia and the French-run Suez Canal.[67] Three weeks later, Mussolini told Ciano that he intended for Italy to demand an Italian takeover of Albania.[67] Mussolini professed that Italy would only be able to "breathe easily" if it had acquired a contiguous colonial domain in Africa from the Atlantic to the Indian Oceans, and when ten million Italians had settled in them.[57] In 1938, Italy demanded a sphere of influence in the Suez Canal in Egypt, specifically demanding that the French-dominated Suez Canal Company accept an Italian representative on its board of directors.[68] Italy opposed the French monopoly over the Suez Canal because, under the French-dominated Suez Canal Company, all Italian merchant traffic to its colony of Italian East Africa was forced to pay tolls on entering the canal.[68]
The local Albanian chieftain who in 1922 had himself proclaimed king as Zog I, failed to create a strong state.[69] Albanian society was deeply divided by religion and language, with disputed borders and an undeveloped rural economy. In 1939, Italy invaded and captured Albania and made it a part of the Italian Empire as a separate kingdom in personal union with the Italian crown. Italy had long built strong links with the Albanian leadership and considered it firmly within its sphere of influence. Mussolini wanted a spectacular success over a smaller neighbour to match Germany's absorption of Austria and Czechoslovakia. Italian King Victor Emmanuel III took the Albanian crown, and a fascist government under Shefqet Verlaci was established to rule over Albania.[70]
Regional patterns
Balkans

The Great Depression destabilised Romania. The early 1930s were marked by social unrest, high unemployment, and strikes. In several instances, the Romanian government violently repressed strikes and riots, notably the 1929 miners' strike in Valea Jiului and the strike in the Griviţa railroad workshops. In the mid-1930s, the Romanian economy recovered and the industry grew significantly, although about 80% of Romanians were still employed in agriculture.   French economic and political influence was predominant in the early 1920s but then Germany became more dominant, especially in the 1930s.[71]
East Asia: Japanese dominance
The Japanese modelled their industrial economy closely on the most advanced European models. They started with textiles, railways, and shipping, expanding to electricity and machinery. The most serious weakness was a shortage of raw materials. Industry ran short of copper, and coal became a net importer. A deep flaw in the aggressive military strategy was a heavy dependence on imports including 100 percent of the aluminum, 85 percent of the iron ore, and especially 79 percent of the oil supplies. It was one thing to go to war with China or Russia, but quite another to be in conflict with the key suppliers, especially the United States, Britain, and the Netherlands, which supply the oil and iron.[72]
Japan joined the Allies of the First World War in order to make territorial gains. Together, with the British Empire, it divided up Germany's territories scattered in the Pacific and on the China coast; they did not amount to very much. The other Allies pushed back hard against Japan's efforts to dominate China through the Twenty-One Demands of 1915. Its occupation of Siberia proved unproductive. Japan's wartime diplomacy and limited military action had produced few results, and at the Paris Versailles peace conference. at the end of the war, Japan frustrated in its ambitions. At the Paris Peace Conference in 1919, its demands for racial parity, and an increasing diplomatic isolation. The 1902 alliance with Britain was not renewed in 1922  because of heavy pressure on Britain from Canada and the United States. In the 1920s Japanese diplomacy was rooted in an largely liberal democratic political system, and favored internationalism. By 1930, however, Japan was rapidly reversing itself, rejecting democracy at home, as the Army seized more and more power, and rejecting internationalism and liberalism. By the late 1930s it had joined the Axis military alliance with Nazi Germany and Fascist Italy.[73]
In 1930, the London disarmament conference angered the Japanese Army and Navy. Japan's navy demanded parity with the United States and Britain, but was rejected and the conference kept the 1921 ratios. Japan was required to scrap a capital ship. Extremists assassinated Japan's prime minister and the military took more power, leading to the rapid decline in democracy.[74]
Japan seizes Manchuria
In September 1931, the Japanese Army—acting on its own without government approval—seized control of Manchuria, an anarchic area that China had not controlled in decades. It set up a puppet government of Manchukuo. Britain and France effectively control the League of Nations, which issued the Lytton Report in 1932, saying that Japan had genuine grievances, but it acted illegally in seizing the entire province. Japan quit the League, Britain took no action.  The US Secretary of State announces that it would not recognize Japan's conquest as legitimate. Germany welcomed Japan's actions.[75][76]
Toward conquest of China
The civilian government in Tokyo tried to minimize the Army's aggression in Manchuria, and announced it was withdrawing. On the contrary, the Army completed the conquest of Manchuria, and the civilian cabinet resigned. The political parties were divided on the issue of military expansion. The new Prime Minister Inukai Tsuyoshi tried to negotiate with China, but was assassinated in the May 15 Incident in 1932, which Ushered in an era of  ultranationalism led by the Army and supported by patriotic societies. It ended civilian rule in Japan until after 1945.[77]
The Army, however, was itself divided into cliques and factions with different strategic viewpoints. One faction saw The Soviet Union is the main enemy, the other sought to build a mighty empire based in Manchuria and northern China. The Navy, while smaller and less influential, was also factionalized. Large-scale warfare, known as the Second Sino-Japanese War, began in August 1937, with naval and infantry attacks focused on Shanghai, which quickly spread to other major cities. There were numerous large-scale atrocities against Chinese civilians, such as the Nanking Massacre in December 1937, with mass murder and mass rape.  By 1939 military lines had stabilized, with Japan in control of almost all of the major Chinese cities and industrial areas. A puppet government was set up.[78]  In the U.S., government and public opinion—even including those who were isolationist regarding Europe—was resolutely opposed to Japan and gave strong support to China.  Meanwhile, the Japanese Army fared badly in large battles with Soviet forces in Mongolia at the Battles of Khalkhin Gol in summer 1939.  The USSR was too powerful. Tokyo and Moscow signed a nonaggression treaty in April 1941, as the militarists turned their attention to the European colonies to the south which had urgently needed oil fields.[79]
Latin America
The Great Depression posed a great challenge to the region. The collapse of the world economy meant that the demand for raw materials drastically declined, undermining many of the economies of Latin America. Intellectuals and government leaders in Latin America turned their backs on the older economic policies and turned toward import substitution industrialization. The goal was to create self-sufficient economies, which would have their own industrial sectors and large middle classes and which would be immune to the ups and downs of the global economy. Despite the potential threats to United States commercial interests, the Roosevelt administration (1933–1945) understood that the United States could not wholly oppose import substitution. Roosevelt implemented a Good Neighbor policy and allowed the nationalization of some American companies in Latin America. Mexican President Lázaro Cárdenas nationalized American oil companies, out of which he created Pemex. Cárdenas also oversaw the redistribution of a quantity of land, fulfilling the hopes of many since the start of the Mexican Revolution. The Platt Amendment was also repealed, freeing Cuba from legal and official interference of the United States in its politics. The Second World War also brought the United States and most Latin American nations together, with Argentina the main hold out.[80]
Sports
Sports became increasingly popular, drawing enthusiastic fans to large stadia.[81] The International Olympic Committee (IOC) worked to encourage Olympic ideals and participation.  Following the 1922 Latin American Games in Rio de Janeiro, the IOC helped to establish national Olympic committees and prepare for future competition. In Brazil, however, sporting and political rivalries slowed progress as opposing factions fought for control of international sport. The 1924 Summer Olympics in Paris and the 1928 Summer Olympics games in Amsterdam saw greatly increased participation from Latin American athletes.[82]
English and Scottish engineers had brought futebol (soccer) to Brazil in the late 19th century. The International Committee of the YMCA of North America and the Playground Association of America played major roles in training coaches.[83] Across the globe after 1912, the Fédération Internationale de Football Association (FIFA) played the chief role in the transformation of association football into a global game, working with national and regional organizations, and setting up the rules and customs, and establishing championships such as the World Cup.[84]
Africa and Asia

End of an era
The interwar period ended in September 1939 with the German invasion of Poland and the start of World War II.[1]
See also
1920s
Roaring Twenties
1930s
International relations (1919–1939)
Diplomatic history of World War I
Diplomatic history of World War II
Interwar Britain
European Civil War
1920s in Western fashion
1930–45 in Western fashion
Great Depression
Great Depression in the United States
European interwar economy
Causes of the Great Depression
Cities in the Great Depression
Dust Bowl
Entertainment during the Great Depression
Timeline of the Great Depression
Timelines
Timeline of the 20th century, since 1900
Timeline of events preceding World War II
Events preceding World War II in Europe
Events preceding World War II in Asia


Further reading
 – 736 pp; basic survey
Berg-Schlosser, Dirk, and Jeremy Mitchell, eds. Authoritarianism and democracy in Europe, 1919–39: comparative analyses (Springer, 2002).
Berman, Sheri. The social democratic moment: Ideas and politics in the making of interwar Europe (Harvard UP, 2009).
Clark, Linda Darus, ed. Interwar America: 1920-1940: Primary Sources in U.S. History (2001)
Dailey, Andy, and David G. Williamson. (2012) Peacemaking, Peacekeeping: International Relations 1918–36 (2012) 244 pp; textbook, heavily illustrated with diagrams and contemporary photographs and colour posters.
Doumanis, Nicholas, ed. The Oxford Handbook of European History, 1914–1945 (Oxford UP,  2016).

Duus, Peter, ed.,  The Cambridge History of Japan, vol. 6, The Twentieth Century (1989) pp 53–153, 217-340. 
Feinstein, Charles H., Peter Temin, and Gianni Toniolo. The world economy between the world wars (Oxford UP, 2008), a standard scholarly survey.
Freeman, Robert. The InterWar Years (1919 - 1939) (2014), brief survey
Gardner, Lloyd C. Safe for Democracy: The Anglo-American Response to Revolution, 1913-1923 (1987) focus on diplomacy of Lloyd George and Wilson
Gathorne-Hardy, Geoffrey Malcolm. A short history of international affairs, 1920 to 1934 (Oxford UP, 1952).

Grift, Liesbeth van de,  and Amalia Ribi Forclaz, eds. Governing the Rural in Interwar Europe (2017)
Grossman, Mark  ed. Encyclopedia of the Interwar Years: From 1919 to 1939 (2000).
 – a view from the Left.

Kaser,  M. C.  and E. A. Radice, eds. The Economic History of Eastern Europe 1919-1975: Volume II: Interwar Policy, The War, and Reconstruction (1987)

Koshar, Rudy. Splintered Classes: Politics and the Lower Middle Classes in Interwar Europe (1990).
Luebbert, Gregory M. Liberalism, fascism, or social democracy: Social classes and the political origins of regimes in interwar Europe (Oxford UP, 1991).


Mowat, C. L. ed. (1968). The New Cambridge Modern History, Vol. 12: The Shifting Balance of World Forces, 1898–1945 (2nd ed.). – 25 chapters by experts; 845 pp; the first edition (1960) edited by David Thompson has the same title but numerous different chapters.
Mowat, Charles Loch. Britain Between the Wars, 1918–1940 (1955), 690pp; thorough scholarly coverage; emphasis on politics ;  
Murray, Williamson and Allan R. Millett, eds. Military Innovation in the Interwar Period (1998)
Newman, Sarah, and Matt Houlbrook, eds. The Press and Popular Culture in Interwar Europe (2015)
Overy, R.J. The Inter-War Crisis 1919-1939 (2nd ed. 2007)
Rothschild, Joseph. East Central Europe between the two world wars (U of Washington Press, 2017).
Seton-Watson, Hugh. (1945) Eastern Europe Between The Wars 1918–1941 (1945) 
 – 550 pp; wide-ranging political, social and economic coverage of Britain, 1910–35
Toynbee, A. J. Survey of International Affairs 1920–1923 (1924) 
Toynbee, A. J. Survey of International Affairs annual 1920–1937  
Toynbee, A. J. Survey of International Affairs 1924 (1925)
Toynbee, A. J. Survey of International Affairs 1925 (1926) 
Toynbee, A. J. Survey of International Affairs 1924 (1925) 
Toynbee, A. J. Survey of International Affairs 1927 (1928) 
Toynbee, A. J. Survey of International Affairs 1928 (1929) 
Toynbee, A. J. Survey of International Affairs 1929 (1930)  
Toynbee, A. J. Survey of International Affairs 1932 (1933) 
Toynbee, A. J. Survey of International Affairs 1934 (1935), focus on Europe, Middle East, Far East
Toynbee, A. J. Survey of International Affairs 1936 (1937) 
Wheeler-Bennett, John. Munich: Prologue To Tragedy, (1948) broad coverage of diplomacy of 1930s
Zachmann,  Urs Matthias. Asia after Versailles: Asian Perspectives on the Paris Peace Conference and the Interwar Order, 1919-33 (2017)
Primary sources
Keith, Arthur Berridale, ed. Speeches And Documents On International Affairs Vol-I (1938)  ; all in English translation

, Mount Holyoke College edition
 Several large collections of primary sources and illustrations