The book is good. It starts out with introducing Holmes, he's a war doctor who was injured. He has a meager army stipend and can't really work because of his injuries so he needs a roommate. And old colleague of his introduces him to Sherlock Holmes. The book is written in first person and is set up as if Watson has just transcribed parts of his personal journal into this short novel. It's a very good format and allows the reader to watch Sherlock along with Watson. That is the most enjoyable part and what makes Sherlock a timeless character. This genius man who is a bit mad but terribly clever. Doyle is careful to keep Sherlock a bit of mystery, he's always one step ahead of everyone else, but at the same time Sherlock will explain what has happened to you. It means that the reader can feel clever alongside Sherlock. It's really a marvelous format.
The television show actually follows the book well. It's not a faithful adaptation, by any means. There are blatant deviations, the murder has extremely different motives from each version. But they really capture the character Sherlock and they do use big plot pieces from the book. If you've watched the show or the Robert Downey Jr. movies you won't be spoiled for books. It's really interesting to see the choices the adaptation made.
Speaking of what they took from the book. The second half of the book is the whole long story of why the murderer wanted to kill these two men. It is totally different than the show and really there was no way that it could ever be adapted. Now I guess this is a touch spoilery but it has to do with Mormons and makes the Mormons out to be these terrible bad guys. It's actually pretty inflammatory. Doyle really depicts the Mormons as a manipulative cult and just harps on polygamy. (Brigham Young himself makes an appearance!) It's like all Mormon stereotypes rolled together. I just never knew that happened in the Sherlock Holmes books. I thought it was all London and pipes and whatever but yeah there is this whole other story in the book and it takes place in Utah. It's not a bad story, it's actually quite action packed. I just could help but be amazed at how badly it portrayed Mormons.
Anyway, I enjoyed it. It was well written, super fun and I will be reading some more Sherlock Holmes this year.