What was his favorite book?

Infinite Jest

Hard to say. All I know is that he was a voracious reader and stuck to non-fictional works for the most part. He was really much better educated than people assume.

Didn't he say that Wittgenstein was the only Jewish philosopher that he agreed with?

beat me to it

behold a pale horse?

Slightly underrated post

I don't get it then

I know that Wittgenstein believed, that the most serious and profound problems and questions and issues can only be discussed in the form of jokes.

No that was probably Otto Weininger (who was an early inspiration for Wittgenstein)

pretty sure Karl May was his favourite author