"The Birds of America" holds the record for being the most expensive book ever published. Created by the naturalist and artist John James Audubon, this book is a masterpiece of art and science. Audubon spent over a decade observing and painting the birds of North America, and the result was a collection of 435 life-sized illustrations of birds, each one accompanied by detailed descriptions of their habitats, behaviors, and even songs.

The book was published between 1827 and 1838, and only 120 complete sets were produced. Each set included four large volumes, and the illustrations were printed on paper that was 39.5 inches by 26.5 inches in size. The book's size, the quality of the printing, and its limited production contributed to its high price.

Today, only a few complete sets of "The Birds of America" exist, and they are rare and highly sought after by collectors. In 2010, a complete set was sold for $11.5 million at auction, making it the most expensive book ever sold.