What's the 3 most important books in IT published in last 5 years?

If you had time for 3 books this year and you'd like to focus on last 5 years or so, which would they be?

They can be technical, theoretical, management-related or in any other way related to IT.

People still buy tech books? I stopped about 15 years ago when I realized most were out of date before they were even printed.

I used to spend several hundred dollars a year on tech books. Back then, it was the only way you could learn anything.

Today, of course, you are correct. I haven't needed to buy a single tech book for years, and it's a lot simpler to learn straight off the Net.