The Bryant and May series, by Christopher Fowler, features Arthur Bryant and John May, two 70-something year old detectives heading the Peculiar Crimes Unit in London, full of slightly odd cops that don't quite fit in at other units, solving crimes that (as their superiors like to remind them) don't really belong in today's world of gang wars and drug related murders. The series starts with Full Dark House, and I've read it and The Water Room so far. I liked Water better than House; I feel like Fowler was just getting his feet under the series in the first book, but you need to read it for the background on the characters and to understand their personalities. These books are richly detailed and darkly atmospheric, and meet my criteria for good mystery novels (must have interesting, engaging characters along with good crimes.) Highly recommended.