Adobe really doesn't sell ebooks (not to say that there isn't a software technical manual or two that they charge for). The place to bet them would be Amazon.com or ebooks.com to name just a couple.
Thanks. I know so little about this, I am hoping you can tell me what format I should be looking for. PDF? Are there places to get books for free?
PDf is all that Adobe Reader can open so that willl be what you want to look for.
Free ebooks (pdf's) are typically either boring manuals or informational pieces or books that are out of circulation. Most of the new stuff will cost money (like the ones at Amazon.com and ebooks.com).
One place that I've gotten a couple of decent ebooks is http://www.planetpdf.com/free_pdf_ebooks.asp. There are a lot of classics available if that's what you like.
You could Google "free ebooks" and see if you can find something else as well.