The Codex Leicester (also briefly known as the Codex Hammer) is a collection of scientific writings by Leonardo da Vinci. The Codex is named after Thomas Coke, who purchased it in 1719; he later became the Earl of Leicester. The manuscript currently holds the record for the third highest sale price of any book: it was sold to Bill Gates at Christie's auction house on 11 November 1994 in New York for US$30,802,500 (equivalent to $53,222,898.79 in 2019).