The Pencil of Nature is a book by William Henry Fox Talbot which was the first commercially published book to be illustrated with photographs. Published by Longman, Brown, Green & Longmans in six fascicles between 1844 and 1846, the book detailed Talbot's development of the calotype photographic process and included 24 calotype prints, each one pasted in by hand, illustrating some of the possible applications of the new technology. It is regarded as an important and influential work in the history of photography and was described by the Metropolitan Museum of Art as "a milestone in the art of the book greater than any since Gutenberg's invention of moveable type."