Desert Star by Michael Connelly

Desert Star is the latest Harry Bosch adventure.  Harry is chosen by his former partner, Renee, to join a new cold case team (as a volunteer, since he's no longer a cop).  He joins to solve a case that has long haunted him--the murder of the entire Gallagher family. But before he can focus on that, Renee makes him help her on the long unsolved case of a city councilman's murdered sister.

Harry is getting older and more frail, but he is still a great (and very determined) detective. Excellent addition to this great series, with kind of a sad ending. There are brief appearances by Harry's daughter, Maddie, and his brother, Mickey Haller (the Lincoln Lawyer).