Alternate history in which England negotiated peace with Hitler in 1941, due to the efforts of a group of upper-class politicians known as "the Farthing set," after the country estate where they planned and plotted.
The novel is set in 1949, and Lord and Lady Eversley have invited their friends to Farthing for a country weekend, an anticipatory celebration of the upcoming vote in which one of their group is expected to become the new Prime Minister. They have also invited their daughter Lucy, which is unexpected; Lucy has been somewhat estranged from her parents (especially her mother) since marrying David Kahn, who is Jewish.
There is a murder at Farthing, and the evidence points to David; Lucy begins to suspect that they were invited so that there would be a convenient suspect to draw suspicion away from the real killer. The chief detective from Scotland Yard, Inspector Carmichael, shares her suspicions, and has secrets of his own that help him to look beyond the planted evidence.
Farthing is a nominee for this year's Sidewise Award, given each year to the best alternate history novel. It was also a nominee (but did not win) earlier this year for science fiction's Nebula Award. I confess that nomination puzzles me; I am not among those who believe that all alternate history should automatically be considered science fiction. There is no SF content here, and I can't find any reason to think of the book as such.
It's a terrifically entertaining book, though, a success both as murder mystery and as alternate history. The mystery story plays fair, and it should be possible for a sharp reader to figure out whodunit; the fascist England that Walton creates is vivid and frightening. Kudos especially to Walton for not wimping out in the final chapters; the ending is not entirely happy, but it perfectly suits the bleak vision of the story.