The done thing
(Book)

"A well-intentioned birthday gift for Lida Stearl leads to the discovery that Clarence Lusk, on death row for the murder of Lida's sister and preparing for his final appeal, is seeking pen-pals. Lida does not think he is entitled to any such consolations, and decides to teach him a lesson: she begins to write him, pretending to be someone else. As she accumulates details of Clarence's life in prison and his connections outside it, her preoccupation with the crime and its echoes intensifies, unsettling those around her and jeopardizing her relationships"--,Provided by publisher.