To call Carson McCullers an eccentric, as some have done, is one of the great understatements of all time. McCullers was deeply, prodigiously weird. Sensitive and vulnerable to an almost pathological degree (the actress Anne Baxter called her “skinless”), she was also a tough survivor, ruthlessly advancing her own agenda and interests at the expense of those she purported to love; “I always felt Carson was a destroyer,” her sometime friend Elizabeth Bowen commented, “for which reason I chose never to be closely involved with her.” McCullers was a monstrous egoist, who put her own talents second to none. (“I have more to say than Hemingway, and God knows, I say it better than Faulkner,” she once asserted, wrongly.) She was an emotional parasite; even her cousin Jordan Massee, who loved her dearly, admitted that “Carson is more demanding than anyone else I have ever known.” Lillian...