In 1945, Sir Arthur Conan Doyle's son, Adrian Conan Doyle, began a collaboration with his father's biographer, John Dickson Carr, to publish twelve new exploits of Sherlock Holmes and Watson (of which one appeared in Life magazine and the other eleven stories were published in Collier's magazine[3]) based on cases that had been referred to in passing in the four canonical novels and 56 original short stories of Sherlock Holmes, but which had never been written up by Watson (see the below mentioned postscripts found at the end of each of the twelve new exploits).

[6] The collaboration was not smooth, as Douglas G. Greene relates in John Dickson Carr: The Man Who Explained Miracles.

[7] There is some doubt about who wrote what—though at times Carr's highly recognisable style breaks through the convention of pastiching the original Conan Doyle stories.

In any case, the book published in 1954 was not a great success at the time, though collectors take an interest in it, and the experiment of writing more new Sherlock Holmes exploits was not repeated by these two writers.

In 1963 John Murray published two paperback volumes which divided the stories into The Exploits of Sherlock Holmes by Adrian Conan Doyle and More Exploits of Sherlock Holmes by Adrian Conan Doyle and John Dickson Carr.