Book #445: The Mourner (1963, Donald E Westlake)
Westlake wrote 17 Parker novels between 62-74 and then 7 more from 97 to 08. The later Parkers are better because they are more intense. The earlier set are not as intense but still fun to read.
This is #4 in the early set. Mostly read on a plane but still enjoyable despite that.
I see there's a new Parker movie out with J.Lo (not playing the lead role).