7% Solution

The Seven-Per-Cent Solution by Nicholas Meyer.

It’s a fun, quick read and probably the first “major” Sherlock Holmes historical team-up. It was made into a rather successful movie starring Nicol Williamson and Robert Duvall as Holmes and Watson, respectively. The book has Watson discovering that Holmes is in severe addiction throes and decides to trick his friend into seeing a new specialist in Vienna. With Dr. Freud’s help, Sherlock remembers and confronts a secret from his past and then they solve a crime.

It’s one of the better non-canon reads and deserves the reputation it has. It is interesting to note that Nicholas Meyer wrote this book when he was only 28. He would later direct another historical fiction, the movie Time After Time, where H.G. Welles chases Jack the Ripper into the 20^th century.

The book was quite popular so you should be able to find it used for very cheap and then movie is on Netflix and pops up on cable once in a while.