Twelfth novel in Donald E Westlake's (a.k.a. Richard Stark) sensational Parker series, The Sour Lemon Score is pure vengeance novel. Parker's part of a four man criminal gang who rob a crate of money being carried from a bank's vault to an armoured car outside. Heist goes smoothly, even with a panicking member. Unfortunately that panicking member of the group, George Uhl, brought along his own plans to murder the other three at the isolated farmhouse where they were to lay low until the heat died down, and take all the cash for himself. Of course as the main character of this series Parker narrowly escapes with his life, but he's in for a long hungry wait and walk until he can escape the area and likelihood of arrest. This of course contributes to the anger and desire for revenge on Uhl, and to get his money back. Problem for Parker though is that since Uhl was pretty much a rookie, and brought in by a dead member of the group, it's not going to be easy to track him down, so Parker's going to have to do a lot of legwork, and make a few people unhappy along the way.
The Sour Lemon Score has a lot of action, and lot of inside the head reasoning and thought patterns of Parker and also uses a lot of nice nostalgia references to really illustrate the time it is set in (it was originally published 1969). Such as a radio voice saying the old "this just in" line before reporting on the robbery. A gun dealer asking Parker if he'd like string put around the boxes containing guns he'd bought (like we're asked if you'd like a bag today). During the initial robbery one of the criminals yelling 'stick em up" and the victims not even laughing one bit at the line. Parker makes a few stupid mistakes that maybe he wouldn't make in other books in this series, a lot coming from him being rather impatient at times such as not wanting to wait a few hours for a go between to return to his store. You do also wonder why he wasn't just shot and killed in one scene as later in the book that character admits he has no qualms with murder and the alternative is a lot less convenient than simple murder, plus they'd know Parker will just come back for revenge. Without these things the enjoyable plot wouldn't work though.
Next novel in the series is Deadly Edge.