If you are looking for Spenser the "private investigator" you only get about half of the equation. There is plenty of "private" stuff, but not much of an "investigation" as Spenser and Paul go about the relatively easy task of finding Paul's mom who has been missing for a couple of weeks. But you DO get plenty of what we love the most: Spenser wit, Spenser justice, and Hawk, too.
Unfortunately, Parker does NOT clear up references in the early novels (God Save the Child, The Promised Land) about a woman Spenser refers to as his "mother" since we are informed that his mother died whilst giving him birth. This isn't a big problem, after all a girlfriend of his father or a favored aunt good have filled the role and gotten the title. Still Parker should have cleared up the apparent inconsistency...
The almost skeletal, almost negligible, plot involving Paul Giacomin's mother hardly sizzles. Hawk and a long chase through the woods save the book. This is a must read for the Spenser fan. Just don't expect anything shocking, or, terribly interesting about Spenser's past.