Muriel Spark weaves her 21st work of fiction, Aiding and Abetting (Doubleday; 166 pages; $21), around a matter of fact: the 1974 disappearance of the seventh Earl of Lucan, who was subsequently charged with bludgeoning his children's nanny to death in a botched attempt to murder his estranged wife. Questions about this scandal have echoed in the British press ever since. Was Lord Lucan guilty? Is he still alive? If so, who helped him escape, and who has been aiding and abetting the fugitive's life in hiding ever since?
Cut to the fictional near present. Hildegard Wolf, a successful Paris psychiatrist,...