Compare prices before you buy
• Add All - Bookstore Price Comparison "searches all the data bases of all the major on-line bookstores. This makes us the biggest book database on the Internet." You can also click on Used & Out of Print Books to search the separate database.
• All Bookstores.com - Compare prices at about 26 web stores.
• BestBookBuys - Compares prices at 28 web stores.

Online stores
• Amazon.com - the on-line bookstore
• Barnes and Noble - on-line bookstore
• Bookbyte - New and used college texts
• Book Lovers: Fine Books and Literature
• Powell's - largest independent bookseller
• University Books
• Varsity Books - text books and more

Out-of-print, rare, used
• abebooks.com - Search for rare, used and out-of-print books. An amazing source. Currently lists 111,000,000 books, for 13,500 book sellers. Each entry has a complete description of the book. Recommended.
• Worldcat - Searches library catalogs, also links to book sellers and webpages which mention the book.

Publishers
• ACQWEB's Directory of Publishers and Vendors - links to publishers home pages & much more