What are books you've read that gave you a very significant change on how you've viewed the world, politics, life, religion, philosophy, etc.?
Machiavelli's The Prince, one of my favorite books. (Although I like the Discourses on Livy better)
Freidrich Nietszche's Human All Too Human, and Die Spracht Zarathustra...although I'm not atheistic (anymore), my philosophy is greatly 'widened' by Nietszche.
Karl Marx's Das Kapital [esp. on reification] ...I'm by no means a "communist" but most people can agree on the at least the critique posed on many of his works.
Frued's Civilization and Its Discontents (also Group Psychology and the Ego)...a lot of which echoes Schopenhauer and Nietszche.
other i'll post it later when I recall...