 He lost his job when the publishing company suffered from the 1929 Great Depression.He wrote critiques on the effects of World War I with his books "Kamerad im Westen" ("Comrade in the West") published in 1930, which became a bestseller, and "Wehrlos hinter der Front" ("Defenseless Behind the Front") in 1931.Between 1919 and 1934, Bossert authored around fifteen books on various topics from ancient Cretan civilisation to European folk art.