What book is Houtarou reading in episode 2 of Hyouka? In episode 2 of Hyouka, Houtarou is shown reading a book throughout the episode. What book is it?
Houtarou is reading On Decadence (堕落論 = Daraku-ron, sometimes also translated Discourse on Decadence), by Ango SAKAGUCHI. 





(image source: this blog)

Sakaguchi was a novelist, essayist, and critic who lived from 1906-1955. He gained immense popularity in the immediate post-war period with his 1946 essay On Decadence, which criticized pre-war Japan as too heavily steeped in bushido culture, and argued that though post-war Japan was decadent, it was better than what came before.

On Decadence is not mentioned in the Kotenbu series of novels on which Hyouka is based.

In an amusing connection, the anime Un-Go (written アンゴ = ango in Japanese and hence pronounced identically to Sakaguchi's given name) was based on one of Sakaguchi's period novels - Meiji Kaika Ango Torimono-chou, loosely "Ango's Tales of Detectives from the Dawn of the Meiji Period".