Is the most interesting and horrifying book I've read in a long time...very tasty!
The premise is that Sherlock Holmes is investigating the Jack the Ripper murders. All well so far. Watson narrates, but the author is saved from reporducing Arthur Conan Doyle's style by emphasising that Watson's contributions were ACD's inventions. The book takes a turn when Watson begins to suspect that his friend is not knows the killer personally, but may be Jack the Ripper himself. A must read for all but the most stringent of ACD's fans.