This is the tenth book in Rankin's Inspector Rebus series. I haven't read them all, and haven't read the ones I have in order: it all depends on which ones I find at the used bookstore. One doesn't have to read them in order, though it helps: in this one two events from Rebus' past are repeatedly mentioned as haunting him, and I had read the book in which one of them happens but not the other.
The series is dark, seriously so. I believe the usual term is “gritty”. Scotland's poverty and social problems are always at the forefront of the crimes, and the language and the food reflects Edinburgh probably all too well. (This one includes a graphic description of a “prawn mayonnaise” sandwich that made me put my head between my knees.) Rebus has a major drinking problem and self-sabotages in his relationships, and there is rarely a traditionally happy ending: criminals get away with it, good people suffer, Rebus does not take the high road.
Dead Souls is no exception to this pattern. It deals with pedophiles, suicide, a serial killer, and other cheerful topics. It's not as rough as Set in Darkness, which was the first Rankin I read and which is like being punched in the gut, especially for a recovering alcoholic. But it is extremely depressing. Rankin's gift is twofold: one, he does not create unrealistic sorrow. You never feel that he has done something cruel to a character simply for the sake of doing so. The characters all behave realistically, and life acts realistically upon them. Two, his plots are (usually) baroque and fascinating enough that you remain hooked despite the grinding litany of reasons Scotland is Tragic. I couldn't put Dead Souls down, and it may be my favorite of his so far. In it he seems to have balanced the mystery plot perfectly with Rebus' self-destruction, so that Rebus is tragic but not a caricature of an alcoholic renegade policeman.
Next up: Committed: A Love Story, by Elizabeth Gilbert, which is a terrible idea but it has been sitting on my to-read list for over a year and I want to just get Gilbert condescending to me about marriage over with. (There's a story about why I even own this book in the first place, and it will provoke lots of ranting on my part. Watch this space! If, um, ranting is your thing.)