SYNOPSIS-Modern Orthodox Judaism — a loosely defined sect that adheres to the strictures of Jewish Scripture, while engaging with the broader world, intellectually and economically — has always been something of a paradox: It embraces modernity and, at the same time, lives by the dictums of an ancient system. Tova Mirvis’s memoir, “The Book of Separation,” chronicles this paradox, and many others, in an intimate tale of leaving a community that served as the literary inspiration for her first two novels, and the bulwark of her life.