Joseph Maurice Ravel (] ; 7 March 1875 – 28 December 1937) was a French composer, pianist and conductor.
 He is often associated with impressionism along with his elder contemporary Claude Debussy, although both composers rejected the term.
 In the 1920s and 1930s Ravel was internationally regarded as France's greatest living composer.
Introduction and Allegro for Harp, Flute, Clarinet and String Quartet (French: "Introduction et allegro pour harpe, flûte, clarinette et quatuor" ) was written by Maurice Ravel in 1905.
 It premiered on 22 February 1907 in Paris.
Louis Charles Bonaventure Alfred Bruneau (3 March 1857 – 15 June 1934) was a French composer who played a key role in the introduction of realism in French opera.
Charles-Camille Saint-Saëns (] , traditionally pronounced ] in French; (9 October 183516 December 1921) was a French composer, organist, conductor and pianist of the Romantic era.
 His best-known works include Introduction and Rondo Capriccioso (1863), the Second Piano Concerto (1868), the First Cello Concerto (1872), "Danse macabre" (1874), the opera "Samson and Delilah" (1877), the Third Violin Concerto (1880), the Third ("Organ") Symphony (1886) and "The Carnival of the Animals" (1886).
Edward Lockspeiser (21 May 19053 Feb 1973) was an English musicologist, composer, art critic and radio broadcaster on music who specialized in the works and life of French composer Claude Debussy and was considered one of the few British authorities on French classical music.
 Lockspeiser studied at the Paris Conservatory between 1922 and 1926 with Alexandre Tansman and Nadia Boulanger and at the Royal College of Music in London from 1929 to 1930 with Charles Herbert Kitson and Malcolm Sargent.
 He was voted into the Académie des Beaux-Arts in 1948 for his services to French music.
Mario Cazes (17 July 1890 – 3 November), was an 20th-century French composer, conductor and violinist extremely popular during the 1920s and 1930s.
Casimir Oberfeld (1903–1945) was a Jewish Polish-born French composer.
 He worked on many film scores and also wrote popular songs of the 1920s and 1930s.
 Following France's invasion by Germany in 1940 during the Second World War, Oberfeld faced increasing persecution.
 Having taken shelter in Italian-occupied Nice he was arrested when the area was taken over by the Germans.
 He was sent to Auschwitz where he died in January 1945.
Jean Baptiste Senaillé (23 November 1687 in Paris – 15 October 1730 idem) was a French born Baroque composer and violin virtuoso.
 His father was a member of Les Vingt-quatre Violons du Roi.
 Senaillé studied under Jean-Baptiste Anet, Giovanni Antonio Piani and in Italy under Tomaso Antonio Vitali and imported Italian musical techniques and pieces into the French court.
 He wrote around 50 violin sonatas.
 He is most well known for a fast 2/4 movement from one of these sonatas, "Allegro Spiritoso", which has had versions published transcribed for a wide variety of instruments, from violoncello to bassoon to euphonium.
Maurice Yvain (12 February 1891 – 27 July 1965) was a French composer, noted for his operettas of the 1920s and 1930s, some of which were written for Mistinguett, at one time the best-paid female entertainer in the world.
 In the 1930s and 1940s he became a major success in the United States and several of his pieces appeared in the famous "Ziegfeld Follies" on Broadway.
 He also composed music for several films of notable directors such as Anatole Litvak, Julien Duvivier and Henri-Georges Clouzot and his music blended with the then "spirit of Paris".
Jean ("Jehan") Titelouze (c. 1562/63 – 24 October 1633) was a French composer, poet and organist of the early Baroque period.
 His style was firmly rooted in the Renaissance vocal tradition, and as such was far removed from the distinctly French style of organ music that developed during the mid-17th century.
 However, his hymns and Magnificat settings are the earliest known published French organ collections, and he is regarded as the first composer of the French organ school.

Question: Introduction and Allegro was written by a French composer regarded as what in the 1920s/1930s?
Answer: France's greatest living composer