Essential Bookshelf
it is soon recognised that they write for the sake of filling up the paper, and this is the case sometimes with the best authors... As soon as this is perceived the book should be thrown away, for time is precious. As a matter of fact, the author is cheating the reader as soon as he writes for the sake of filling up paper; because his pretext for writing is that he has something to impart... It is only the man who writes absolutely for the sake of the subject that writes anything worth writing. What an inestimable advantage it would be, if, in every branch of literature, there existed only a few but excellent books!
-- Arthur Schopenhauer, "On Authorship and Style"
Disclaimer: a lot of the books here are recommendations from elsewhere that I've collected. I do try to be critical about what gets in, but I haven't personally read and vetted all of them like with the rest of chuuni.org.
Essential Essentials
Rationality: From AI to Zombies is the one book that should be required reading for the entire human race. I cannot emphasize this enough.
Harry Potter and The Methods of Rationality is a brilliant fanfic that borrows from the original Harry Potter universe to create something that far surpasses the original work. The series spawned an entire new genre that became known as Rationalist Fiction.
Since the length of the story might be intimidating, I've collected a few quotes from the story to help pique your interest.