Mormonism begins with a memoir: Joseph Smith kneeling in a grove until two-thirds of the Godhead appear and promise him a quixotic religious renown. Since then, the faith Smith birthed has raised up memoirs as gritty as Parley P. Pratt's quasi-canonical Autobiography or as luminously sarcastic as Elna Baker's New York Regional Mormon Singles Halloween Dance. Grafted somewhere into those works' genealogy comes this boyhood memoir,...