The World's Most Expensive Book

The world's most expensive book is up for auction. So, who's bidding? :D

A rare copy of John James Audubon's "Birds of America," billed as the world's most expensive book, is up for sale alongside a first edition of Shakespeare's plays at an auction to set book lovers' pulses racing, Sotheby's said Thursday.

One of only 100 or so remaining copies of "Birds of America" is valued at between 4 million pounds and 6 million pounds ($6.2 million and $9.2 million), while a Shakespeare First Folio from 1623 is expected to fetch at least 1 million pounds ($1.54 million).

Sotheby's books expert David Goldthorpe said the two tomes are "the twin peaks of book collecting." The books come from the estate of the 2nd Baron Hesketh, an aristocratic book collector who died in 1955. The auction house is selling them in London on Dec. 7.

Another complete copy of "Birds of America" was sold by Christie's for $8.8 million in 2000, a record for a printed book at auction.

It is one of the most significant — and beautiful — published works of natural history, and rarely comes up for sale. Only 119 copies remain, and all but a handful are in museums, libraries and universities.