Have you been looking for good books, and at the same time wanted your money to go to good causes? Well, now's your chance! Snag yourself some books from the Humble Book Bundle featuring No Starch Press. Pay more than the average and really get your money's worth.
I've been keeping my eye on the Linux Command Line book and was so happy to see this bundle. I really like the style that No Starch uses for their books. I picked up a copy of their Practical Packet Analysis out of interest of how network traffic worked. It provided a fair bit of detail without being overwhelming. Realistically I should have picked up their TCP/IP book to maybe just learn about one protocol. I just couldn't justify paying the cost for it.
Speaking of cost, one of these books by itself might cost more than what the average price is going for at this time. So you're saving yourself some money, getting good books, and helping good causes. Win. Win. Win.