A lost collection of personal papers belonging to Sherlock Holmes creator Sir Arthur Conan Doyle goes on show for the first time on Thursday.
About 80% of Conan Doyle's lost papers have never been published
The papers and other artefacts include a first sketch of Sherlock Holmes in the novel A Study in Scarlet.
The papers, found in the offices of a London legal firm, went missing during a dispute over his estate 40 years ago.
The collection, valued at about £1.5m, is on display at Christie's in London - it will be auctioned on 19 May.
The collection of 3,000 items includes personal letters and hand-written manuscripts - 80% of which have never been published.
It also includes personal effects taken from Conan Doyle's writing desk after his death in 1930.
The sketch of Sherlock Holmes in A Study in Scarlet, with the original title A Tangled Skein crossed through, is expected to fetch up to £150,000.
Jane Flower, Christie's manuscript consultant, said the papers were first referred to in a biography of Conan Doyle by John Dickson Carr in 1949.
"The whereabouts of this material was previously unknown," said Ms Flower.
"It is for this reason that no modern day biography of the author exists."
"Scholars and admirers of Sir Arthur Conan Doyle have long been tantalised by the list of the writer's personal papers published in the authorised biography by John Dickson Carr."
Tom Lamb, the head of Christie's books and manuscripts department, added: "Opening the dozen or so large cardboard boxes, which had housed the archive
since the 1960s, was a spine-tingling moment that I will never forget."
The collection also includes letters received from public figures, including Winston Churchill, Oscar Wilde, Bernard Shaw, PG Wodehouse and the US president Theodore Roosevelt.