"De Avonden"/"The Evenings" by Gerard Reve. It is a small masterpiece set in the period after WWII in The Netherlands. It deals with themes like the post-war boredom, but also more general themes like emptiness of personal relations and how life can seem pointless in your early twenties.

I always think of it as the Dutch version of The Catcher in the Rye, which deals with similar themes. But the main character in The Evenings is decidedly less of a prick than Holden Caulfield hahaha.

By some great mistake of the book's editors in its time, this masterpiece did not get translated in Enlish until last year or so. If it would have been translated in the years after it was written, it would surely have been a major hit in the Enlish speaking world like it was over here.