Drop of the Hard Stuff by Lawrence Block

Slow, but Block's characters are so likable and interesting that the book was a pleasure. PW: Matthew Scudder is facing his demons. Forced out of the NYPD, he's given up the drink. He's thinking seriously about his relationship with sometime girlfriend Jan. Then he runs into "High-Low" Jack Ellery, a childhood friend from the Bronx. They're two sides of the same coin: Scudder once solved crimes as a detective. Ellery committed them. In Scudder, Ellery sees the moral man he might have become. In Ellery, Scudder sees the hard-won sobriety he hopes to achieve.