The historic manuscript, signed by Doyle, will be sold by Sotheby’s in New York this June

An autographed manuscript of The Sign of Four, the iconic Sherlock Holmes novel by Sir Arthur Conan Doyle, is set to become the most valuable item by the author ever offered at auction. The manuscript, which dates back to 1889, is estimated to fetch between $800,000 and $1.2 million (£633,000 to £949,000) during an auction hosted by Sotheby’s in New York this June, as part of their Book Week event.

The manuscript, which features two signatures by Conan Doyle, also contains edits made to “Americanise” the text before its publication in the United States. The manuscript will be sold alongside a set of letters exchanged between Conan Doyle and JM Stoddart, editor of Lippincott’s Monthly Magazine, where The Sign of Four first appeared. These letters offer a unique insight into the book’s progression, including deliberations over its title and details about the printing and illustrations.

Richard Austin, Sotheby’s global head of books and manuscripts, described the item as an “important historical treasure” and highlighted its rarity. “This autograph manuscript of The Sign of Four offers a unique glimpse into Conan Doyle’s writing process,” he said. “Together with the letters, it provides a rich tapestry of insight into preparing Holmes for an American audience.”

The manuscript and letters are part of a larger collection being auctioned from the library of Dr. Rodney Swantko, a renowned collector who passed away in 2022. Swantko’s library included over 40 rare books and manuscripts, including works by Charles Dickens, F. Scott Fitzgerald, and Edgar Allan Poe.

Also up for auction is Sidney Paget’s original drawing for The Death of Sherlock Holmes from the short story The Final Problem, which greatly influenced the modern image of the detective. Additionally, a rare first edition of Edgar Allan Poe’s Tamerlane and Other Poems from 1827, one of only 12 copies known to exist, is expected to sell for $400,000 to $600,000 (£317,000 to £475,000).

The auction will take place in New York from June 11 to 26, 2024.