[Peter Ansoff]

If you need to track down a book, take a look at the American Book Exchange (AbeBooks Official Site - New & Used Books, New & Used Textbooks, Rare & Out of Print Books). This site contains a huge database of new and used books that are available from booksellers all over the world. You can search by author, title, edition, condition, price range, etc., and purchase the books online. You can also set up a "want list", and they'll email you whenever something matching your wants appears in the system.

The only (very minor) drawback is that ABE Books itself is headquartered in British Columbia, so that purchases by US customers are considered to be "foreign transactions" by credit card companies. The transaction fee is very small (only a dollar or so in most cases). However, it's annoying, since most of the bookstores you're actually buying from are in the USA.

Despite that minor issue, ABE Books is a great site. I'm a regular customer of theirs, and I highly recommend it. I've found some great deals there on flag-related books.

Peter Ansoff