Deborah Crombie succeeds on at least three levels in the continuation of the Duncan Kincaid/Gemma James series.
First, she skillfully develops the historic and contemporary meaning of Southwark, where the story is set. Architectural details, anomalies of language, and anecdotes of days gone by provide a rich and believeable backdrop. Yet the setting informs, rather than overwhelms, the story: no risk of drowning in meaningless detail.
Second, the plot nests several mysteries without requiring all the characters to run into each other. Though nuanced, the questions at the story's center differentiate themselves sufficiently to make the reader follow closely the final pages. It would be hard not to care about how each problem resolves and Crombie conscientiously wraps up each of the plots.
The primary reason to care so much about the plots is that the characters, both familiar and those making one-time appearances in the series, show rich diversity in character and within characterizations. About the few characters who lack depth, the reader is likely to think simply that -- well, they lack depth. It is true in life, so why not in fiction? But most of the personalities show the range of how well and how poorly people respond to difficulty. Their interactions are anything but predictable.
When I pick up a book by this author, I always mean to make it last because I savor the tensions between characters, being immersed in the sights and sounds and smells of a foreign place, and the lovely economy of language in dialog and description, alike. And Deborah Crombie does not shirk from putting out a multi-course feast for the mystery reader. The problem, though, is that the stories she creates invariably drive me into turning pages. I tend to finish her books quickly because my curiosity drives me on, even as I want the story to last longer and longer.
A tiny criticism: a personal subplot has strung out over several books. It seems artificial that it remains unresolved. But that's a fly in the neighborhood -- hardly a fly even near the soup of this exciting and interesting book.