No Starch Press has released an awesome set of hacking/IT ebooks through the Humble Bundle https://www.humblebundle.com/books/hacking-reloaded-books
My personal favourites are Metasploit and Packet Analysis.
If you ever wanted to learn to hack and like donating to charity, have a look.
Disclosure: I'm NOT in any way affiliated with Humble Bundle or No Starch Press, I just appreciate the great work of both companies and have spent a fair amount of money with them, because they are bloody good.
