A rare edition of John James Audubon's "Birds of America" sold for more than $10 million at a London auction Tuesday — making it the...

LONDON — A rare edition of John James Audubon’s “Birds of America” sold for more than $10 million at a London auction Tuesday — making it the world’s most expensive book.

Some of the world’s wealthiest book collectors had been anticipating the auction for months: it represents a chance to own one of the best preserved editions of Audubon’s 19th-century masterpiece, with its 435 hand-colored illustrations.

The book sold for $10.3 million at a Sotheby’s auction to an anonymous collector bidding by telephone, the auction house said.

Each individual picture is so valuable there have been some fears the volume could be broken up and sold as 435 separate works of art. Experts believe that unlikely: the tome is probably more valuable intact.

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“Audubon’s ‘Birds’ holds a special place in the rare-book market for several reasons,” said Heather O’Donnell, a specialist with Bauman Rare Books in New York. “The book is a major original contribution to the study of natural history in the New World.

“It’s also one of the most visually stunning books in the history of print: the scale of the images, the originality of each composition, the brilliance of the hand coloring.”

Audubon was part naturalist, part artist, and possessed a rare, almost unequaled ability to observe, catalog and paint the birds he observed in the wild. Experts say his book, originally published in 1827, is unmatched in its beauty and also of considerable scientific value, justifying its cost.

Pom Harrington, owner of the Peter Harrington rare book firm in London, said it has been 10 years since the last complete edition of “Birds of America,” with all of the illustrations, has been auctioned — and that was sold for $8.8 million by Christie’s auction house, a record for a printed book at auction.

The “Birds of America” plates were printed in black and white and hand-colored afterward. That made the production process extremely expensive, especially, Harrington said, because it was carried out by “the best artists of the time.”

The collection, made from engravings of Audubon’s watercolors, measures more than 3 feet by 2 feet because Audubon wanted to paint the birds life size.

The size of the illustrations makes them extremely valuable as stand-alone piece of arts, which makes the complete edition vulnerable to being broken up so the individual prints can be sold one by one.

Harrington said the wild turkey that is depicted in the first big plate of the book can be sold for $200,000.

Audubon, who died in 1851, made an epic voyage down the mighty Mississippi after his dry-goods business failed, taking only a rifle, an assistant, and a drawing pad, making illustrations of as many birds as he could find.

He did not find a printer in the United States willing to take on the book, with its oversize illustrations, so he sailed to England, eventually finding printers in Edinburgh, Scotland, and in London.

The volume is seen as a vital piece of American history, Harrington said.

“It is the most important natural-history book for America,” he said. “That is the main point. It screams Americana. For an American patriot, it is the greatest book on American heritage — there is no competition.”