The Beekeeper's Apprentice (Laurie R. King)

The Russell & Holmes series is a substantial deviation from the typical Holmes story, but (at least for the first ten books) an exceptionally successful one. Russell is a brilliant young woman who is a match for Holmes in every way, and they fall in love while solving crimes. Their genuine pleasure in one another's company is what makes the romantic elements plausible. They recognize one another, and that recognition bridges the differences between them: she's young, Jewish, half-American, but they are still the same.

As for the mysteries themselves, the earlier books are wonderfully constructed. The later ones can occasionally be gimmicky, but they are still well above average. Best of all, King never makes the mistake of trying to write like Doyle would, which would tip these toward pastiche. Instead, she centers Russell's voice, which not only creates a new emotional register for the stories but also unlocks a whole new set of interesting premises.