This may be an interesting read for the Sherlock Holmes fans out there. "The Fifth Heart" by Dan Simmons is a novel which features Sherlock Holmes and a number of historical people - Samuel Clems, John Hays, Henry Adams, President Garfield and Henry James - just to name a few. The setting is primarily in the United States in the years between Holmes at Reichenbach Falls and his reappearance in London.
The central plot is Holmes working to prevent the assassination of President Garfield. There are also a peripheral case Holmes is presenting as the reason for him to be in America. The most interesting subplot though is Holmes seeking to answer the question of "Am I real or just a fictional character?" Henry James is the unwitting Dr. Watson in this novel but the narrator is a never identified. The book also has appearances and a interesting take on Professor Moriarty and Irene Adler.
Over all, I found the 617 pages to be entertaining and a quick read. I read over the course of three days. On the negative, the writer at times gets lost in minutia on subjects which I feel where included to "grow" the word and page count. This is not the Sherlock Holmes of Arthur Conan Doyle and Dr. Watson (they are both mentioned a number of times) but he does keep to many of the characteristics of the original Holmes.