Question: Which Finnish writer was very influential between 1918 and 1939?

Context paragraphs:
Rautatie: Rautatie (Finnish for "railroad") is the first novel by the Finnish writer Juhani Aho, published in 1884.  Its style has been called national miniature realism.  The novel is about the quiet life of a couple living in the middle of the woods and their attempts at imagining what a railroad is based on what they have heard.  "Rautatie" is one of the classics of Finnish literature, and has had more than twenty editions by the start of the 21st century.  It has been called Aho's first "artistic full hit".  In 2007, WSOY published a perfect copy of the 1892 colour edition illustrated by Eero Järnefelt.  A TV film by the same name was made based on the novel in 1973.  The novel has also been adapted to numerous plays.

Frans Eemil Sillanpää: Frans Eemil Sillanpää (   ) (16 September 1888 – 3 June 1964) was one of the most famous Finnish writers and in 1939 became the first Finnish writer to be awarded the Nobel Prize for literature "for his deep understanding of his country's peasantry and the exquisite art with which he has portrayed their way of life and their relationship with Nature".

Otto Manninen: Otto Manninen (13 August 1872, Kangasniemi – 6 April 1950, Helsinki) was a Finnish writer, poet, and a celebrated translator of world classics into Finnish language.  Along with Eino Leino in the early 20th century, he is considered as a pioneer of Finnish poetry.  Manninen translated the works of Homer, Sophocles, Euripides, Heine, Ibsen, Petőfi and Runeberg into Finnish.

Olavi Paavolainen: Olavi Paavolainen (1903 - 1964) was a Finnish writer, poet, essayist and journalist.  During his early years, he went under the pseudonym of Olavi Lauri.  Paavolainen was the central figure of the literary group Tulenkantajat ('The Flame Bearers') and one of the most influential literary opinion leaders between the two World wars in Finland.  He represented liberal and European-oriented views of culture and had an eclectic eye for new ideas.

Lempi Ikävalko: Lempi Ikävalko (9 May 1901 in Ruskeala, Finland – 1994 in Helsinki) was a Finnish writer, poet, actress and performance artist.  She spent much of her adult life as a journalist in the United States but she strongly identified with her roots in Karelia—in Finnish, "Karjala", the region considered the cradle of Finnish mythology because the Kalevala, the national epic poem, came from there.  (Note: since World War II Karelia has been divided between Finland and Russia.)

Maila Talvio: Maila Talvio née Winter, married Mikkola (October 17, 1871, Hartola – January 6, 1951, Helsinki), was a Finnish writer.  Talvio was a leading Finnish writer on the temperance question and several of her works were translated into Swedish and other languages.

Einari Vuorela: Einari Arvid Vuorela (17 August 1889, Keuruu – 10 July 1972, Helsinki) was a Finnish writer.  He was born in the village Jukojärvi in a family of 10 children, and started his studies at Multia.  He became a teacher in Jyväskylä in 1914.  His wife from 1939 was writer Laura Soinne.

Henrik Tikkanen: Georg Henrik Tikkanen (9 September 1924, Helsinki – 19 May 1984, Espoo) was a Finnish author, known primarily for anti-war literature.  Several of his works are either autobiographical or semi-autobiographical.  Though Finnish, he published primarily in his mother tongue, Swedish.  He was born and lived much of his life in Helsinki, and died of leukemia in Espoo.  He was married to the Finnish writer Märta Tikkanen.

World war: A world war, as it is commonly understood, is a large-scale war involving many of the countries of the world or many of the most powerful and populous ones.  World wars span multiple countries on multiple continents, with battles fought in many theaters.  While a variety of global conflicts have been subjectively deemed "world wars", such as the Cold War and the War on Terror, the term is widely and generally accepted only as it is retrospectively applied to two major international conflicts that occurred during the 20th century: World War I (1914–1918) and World War II (1939–1945).

Walter de Camp: Walter de Camp (born "Kari Lempinen"; d. 5 April 2017) was a Finnish writer.  He wrote about partying, restaurants and celebrities in the Finnish City magazine.  There is also a drink named Walter de Camp after the writer.  It was designed by Jasu Piasecki after the short description given by the writer: "It has to contain whiskey, be a short drink and taste really good."

Supporting paragraphs: Olavi Paavolainen World war
Answer: Olavi Paavolainen