Thinking, Fast and Slow

This is the Bias Bible. If you want to get a brief overview of how your brain works, and lots of information on how you aren't the rational actor you see yourself as, this is the book.Kahneman won the Nobel Prize in Economics for his work on human judgement covered in this book, and played a key role in the development of the field of behavioral economics. If you read one book on the brain, this is the one.

(If this is overwhelming and you want an accurate, but less in depth alternative, I also highly recommend Thinking in Bets by Annie Duke.)

Few books have explained more to me than Thinking Fast & Slow.

All about how people make decisions and generally comprehend the world around them - massively informative and worth the slog.