No, not the Roy Walton card trick.
I love reading and collecting magic books, and there are many titles that are out of print that I would happily pay almost anything for, should they somehow crop up or become available. I've recently discovered a couple of website resources that I thought to share with you, if you also have an interest in purchasing hard-to-find magic books, apparatus, and ephemera.
The first is www.collectingmagicbooks.com operated by Philip David Treece. A conservator by trade, he runs the magic history blog www.collectingmagic.co.uk
CollectingMagicBooks.com has everything from antique tomes to new instructional books, categorized by subject matter and age, and available for sale worldwide. Based in the UK, shipping costs to North America can be enormous; however, it's a small price to pay for that book that you've been searching out for years.
If you're more interested in magic props, posters, and various bits of history other than books (but still want books as well) check out www.quickerthantheeye.com in Chicago. With new items uploaded to their site every week, they have quite a range of rare to semi-rare magic books and vintage props. Their posters run from modern reproductions to original lithographs, and their "ephemera" section is a treasure trove.
If you are interested in collecting magic, or if you're looking for an old book, you can try eBay, but I would recommend checking with these sites first!