This is one of the best "Dr Jekyll and Mr Hyde" follow-up books I've ever read. It really catches the spirit of Old Victorian London, and the storyline is most of the times credible. Even though you know the ending and you know Dr Jekyll's secret, this book still manages to be exciting, and it is very well-written indeed. The only argument is, when you know the original "Dr Jekyll and Mr Hyde" well, many of the facts in this book are alredy known to you, and it's a bit boring to read them all over again. But still, a very good book, and I recommend it to Holmes and Jekyll fans alike.