Reader's Digest Photography Manual is classic. It covers all the basics and is old enough that you can read it for free from a library.
Then, I'll second the recommendation for
Understanding Exposure by Bryan Peterson. Read it once you get the basics from another book since this
one only covers exposure.
Even more important is a book on composition which I would recommend as
The Photographer's Eye by Micheal Freeman. This is the best book on compositon in my opinion. You can read
my review of it to know more.
Finally, the one which influenced me the most is
National Geographic's Photography Field Guide. Read it several times and this one is about putting photography in practice. If you plan to do travel photography or just general unplanned shooting, this is an excellent book.
Once you get the basics, look for books on photography themes that you like.
Good luck and have fun!
- Itai