If you're into rare fantasy books, I recommend A Voyage to Arcturus, by David Lindsay. It's a mix of epic travel with philosophy and speculation, plus the small bit of sci-fi so typical in early 20th century fiction books. Very Nietzschesque, sometimes reminiscent of Gustav Meyrink's The Green Face due to certain themes, but more misanthropic and tending-towards-depression (but not suicide-inducing, don't worry) than the novel of the Austrian author.
    Dry style, even laughably crude, with more interest in the ideas exposed than in developing the characters' psychology and the world-building, which is admirable.

A rara avis of a book.