This book has been prepared by the Company of Mary, the religious community founded by St. Louis de Montfort himself, to serve as both an introduction to his spirituality of total consecration and as a guide for those who would prepare themselves to make his Act of Total Consecration to Jesus through Mary. It is also the fruit of the same Act of Total Consecration lived out in years of missionary service to Our Lord and Our Lady in the Roman Catholic Church which the Company of Mary joyfully makes available to the people of God.