A single handwritten page from Charles Darwin's On the Origin of Species has sold for $250,000.
It proved the star lot of a sale of rare books and manuscripts at Sotheby's New York on June 14.
The text corresponds to chapter 7 (Instinct), page 238 although it differs slightly from the published version.
Darwin began hurriedly writing up his theory of evolution after fellow scientist Alfred Wallace issued a paper laying out his early findings on the subject in 1855.
Having spent years percolating his ideas, Darwin was not about to be pipped at the post.
The book was finally published in 1859, 30 years after the first Beagle expedition.
Pages from the manuscript copy of the book are extremely rare, as Darwin threw most away after publication.
Only around 45 are known to have survived to the present day.
A first edition, second issue copy of Walt Whitman's Leaves of Grass made $125,000.
The second issue was the first to be published in the UK.
Leaves of Grass is considered one of the most important works of poetry ever published in America.
It proved controversial on its release due to its frank sexuality, and was banned in several states.
The original 1855 publisher, Osgood, refused to republish without changes to the text and so Whitman took it elsewhere.
As is often the case, banning the book served to massively improve its sales.
You can check out all our books and manuscripts for sale here.
Please sign up to our free newsletter to receive exciting news about art and photography auctions.