Dr. Jekyll and Mr. Holmes — Loren D. Estleman

Sherlock Holmes has already encountered the evil young hedonist Edward Hyde, and knew he was strangely connected with Henry Jekyll, the respectable young doctor. It was not until the Queen herself requested it, however, that Holmes was officially on the case of the savage murder of Sir Danvers Crew. Here, then is the account of that devilish crime as recorded by Dr Watson...