Books I recommend:

 


Programming the 65816
A good book to get a bunch of info about the 6502, 65C02 processors, the assembler instructions, and corresponding opcodes.


Hacker’s Delight
If you’re fond of low level and bitwise operations like me or want to increase that skill, this book is a must-read.
It sums up a lot of smart ways to do things and give you the keys to a better understanding.
It really opens the doors to becoming a better developer.

Hacker’s Delight: Second Edition
The Hacker’s Delight books remind me of the storybooks for toddlers: you can open them at a random page and you’ll always get a nice surprise, a new knowledge ready to get caught. How neat!
This second edition comes with some corrections and new chapters (crc, ecc, …).