If you could have any one computer related book for free which one would it be and why?

I have a $40 gift certificate to Borders Bookstore, and I'll probably be using it in the next few months. Thing is I'm not sure which book I would want (I'm not big on reading books either at all lol), so I'm sure by hearing what book you would like to have I could get a good idea for mysefl. I already got The C++ Programming Langague: Special Edition less than a month ago, as well. Hmmm...

Btw, I'm not expecting anyone to directly recommend a book for me, either.