Fuera de quicio enters the disorder of a family that adopts a chimpanzee, Fern. After a few years, they were forced to give Fern back, causing a series of traumatic changes: the melancholy mother, alcoholic father, the eldest son leaving home to search for Fern, and Rosemary -- the indirect protagonist of the story -- lives the rest of her life obsessed with taking the blame for losing her sister. This novel is an unlikely cross between a psychological thriller and scientific essay. Karen Joy Fowler manages this hybrid with enviable ease and creates a plot that is her most ambitious to date.