Biographies of who don't ""leap"" over convent walls, but accept the joys and austerities of religious life with equal equanimity, soldom make absorbing reading. Lub in To Grow Holy Merrily, Mother Maria Tommasini emerges as a woman of spirit, conviction and indomitable courage. Her life -- spanning the 88 years between 1827 and 1915 -- was an adventure story marked by a truly heroic love of God. A religious in the Society of The Sacred Heart in her native Italy, young Mother Tommasini was sent to the Society's new-famed school in Manhattanville, New York. Later assignments led to Cuba and Canada, and eventually she established the first Sacred Heart convent in Mexico. Religious persecution dogged her footsteps, but she found ways of outwitting the most wily pursuers. Her story reflects the mirth and joy which filled her own life so completely that she advised young novices ""to love God and grow holy merrily"". Too bad that M. K. Richardson tends occasionally to make her characters round stilted and implausible. Such banal conversation would certainly never have characterized so appealing a person as Mother Tommasini.