A handwritten manuscript page from Charles Darwin's On the Origin of Species could make $200,000-300,000 at Christie's.
It corresponds to chapter 7 (Instinct), page 238 although there are a number of differences between this and the published text.
Leaves from the manuscript, which was compiled hastily between 1855 and 1858, are extremely rare.
Darwin threw most of it away after publication, with around 45 pages out of 600 known to have survived.
Only five have ever appeared at auction.
Darwin was still gathering evidence for his theory of evolution in 1855, when fellow scientist Alfred Wallace published a tentative paper proposing the same thing.
Worried that his life's work was about to be eclipsed, Darwin rushed to write and publish his seminal book.
Pages written in Darwin's hand are highly sought after, with a letter laying out his lack of faith in religion selling for $197,000 at Bonhams last year.
A rare copy of William Bradford's The Arctic Regions (1873) carries an estimate of $100,000-150,000.
Bradford was an American painter and photographer who specialised in the Polar Regions. The book was published for subscribers (Queen Victoria among them).
It's not known how many were produced, but it's likely to be well under the proposed 300.
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