The Good Soldier Schweik by Jaroslav Hasek (The Fateful Adventures of the Good Soldier Švejk During the World War #1-4)

The Good Soldier Schweik is the story beginning in Prague with news of the assassination in Sarajevo that precipitates World War I. Schweik displays such enthusiasm about faithfully serving the Austrian Emperor in battle that no one can decide whether he is merely an imbecile or is craftily undermining the war effort. However, he is arrested by a member of the secret police after making some politically sensitive remarks, and is sent to prison. After being certified insane he is finally transferred to a madhouse, before being ejected. This is the Czech classic of anti-war satirical humor.

Paperback, 1963

Goodreads: 4.09