While there's plenty here for the Sherlock Holmes fan, Dirda also discusses Conan Doyle's other works, including the wonderful Professor Challenger stories, the stories of the macabre, and the non-fiction, including Through the Magic Door and some of the writings on spiritualism.
It's always interesting to read about another person's first memories and experiences with Conan Doyle. Dirda vividly recalls his first ventures into the Sherlock Holmes canon, which I don't, but I definitely remember the first time I read The Lost World (my original copy, which is still around somewhere, though much-read now, was a terrible Wal-Mart paperback edition with a lurid orange "99¢" blob printed right on the cover). And I'm pretty sure I wore out my local library's copy of Round the Fire Stories. While the Holmes stories are great, I enjoy some of the other short stories even more, and Dirda's book, as an introduction to the whole range of Conan Doyle's works, is most welcome.