I agree @crua9 and hacking is especially a skill that is learnt by practice rather than pure theory. That’s why dynamic environments like websites and video’s generally provide better ways of teaching stuff and allowing practice in a ‘safe’ environment. However, I understand that sometimes it may be nice to read a book about the topic.
Myself, I got most of my knowledge from my software engineering background and the rest by websites, blogs, videos, tutorials, articles and practice, practice, practice. However, I did like the book that I recommended earlier.
Can you recommend any good sources (books / websites / blogs / etc) for hacking?