This slipped by me in February, but today I learned A Man Named Baskerville is reviewed positively at Melisende’s Library:

This is the much needed backstory of the character of Stapleton from Conan Doyle’s “Hound of the Baskervilles”. It is exceedingly well done and in keeping with Conan Doyle’s original story. … Heartily recommended for lovers of Holmes and those looking to add to their own Sherlock Holmes collections.

Thanks, Melisende! Full review here, more information on the book here, and Amazon page here.