Since I have a Sherlock Holmes library, and not a collection, every book in its is – by definition – a reference book. Which one do I use most often?
Next to various editions of the Canon itself, the one I turn to most is The Encylopeadia Sherlockiana by the late Jack Tracy, first published in hardcover in 1977 by Doubleday & Co. I also have an Avon paperback edition and a later hardcover version by Gramercy which carries a different name, The Ultimate Sherlock Holmes Encyclopedia.
Speaking of names the Tracy book is not to be confused with the similarly named Encyclopedia Sherlockiana by Mathew E. Bunson or The Sherlock Holmes Encyclopedia by Orlando Park, which I also own.
The subtitle of the Tracy book is A Universal Dictionary of the State of Knowledge of Sherlock Holmes and His Biographer, John H. Watson, M.D. But it’s actually more than that. It has entries on everything from the letter A to Zoology, some of them quite lengthy. I most often use it to remind myself in which story a character or unrecorded adventure appears.
My friend Joel Senter, a veteran Sherlockian, commented to me over the weekend that only once has he ever failed to find something he was looking for in The Encylopeadia Sherlockiana. My own experience over almost 40 years has been similar. If this book isn’t on your shelves, it should be. Used copies are readily available.