While our Cryptanalyst Handbook is a great place to start if you are a beginner, the more experienced codebreakers among you might want something more advanced. We have you covered! Longtime Cipher Challenge competitor and community organiser, Madness, wrote an entire book on the subject and made it free for competitors. I would post a link here, but maybe it is better to send you over to the BOSS Library to find it; you never know what else you might discover that way!
