Buying Used and Rare Books on the Net
There are literally thousands of booksellers selling tens of millions of used and rare books on the net right now. The Advanced Book Exchange had over 6,900 booksellers subscribed and 23 million books listed as of November 6, 2000. And that's just one site (albeit the largest). There is a treasure trove of out-of-print books out there, but it can be hard to wade through and actually find them.
If you need help finding a book, start with the search tips. It'll help you develop a search strategy, and lists many possible sources, including:
For those of you who are concerned about the dangers of buying on the net, try the article on Buying Used Books on the Net. This will give you some tips on spotting trouble before it happens.