With generosity, loyalty to her mentors and peers, attention to detail, and a sense of humor, Laura Young has given us an up close and personal look at the raising of a gifted ballerina, coupled with-at last-a history of the founding and early decades of the Boston Ballet. Her book relates the improbable staying power of a dance company that planted itself on the inhospitable shores of Puritan New England to become one of the region’s indispensable treasures.