Turn of Mind by Alice LePlante

The initial conceit of the novel -- that a distinguished, brilliant orthopedic surgeon specializing in hand surgery now suffers from Alzheimers and assorted dementia and can no longer remember clearly whether or not she did or did not kill her best friend (who was found with four fingers severed from her hand) who lives three houses down -- is great. But it suffers in execution, as credulity is strained in accepting an effecting, detailed first-person narration spanning 60 years by someone with memory problems. However, the whodunit plot begins to fade in importance as the narrator's world becomes increasingly facetted and simultaneously dim. As a portrait of a mind giving its own eulogy, the book is alive and ferocious.