virus

Hands down the most expensive book (not counting those not in print for some time, like Gutenberg Bible and such) I've ever come across. One of the largest, too.
http://www.amazon.com/Comprehensive-Organic-Functional-Transformations-Second/dp/0080442560/ref=sr_1_1?ie=UTF8&s=books&qid=1244997135&sr=1-1