Saxum— the Latin word means rock— is the nickname that St. Josemarí a Escrivá , founder of Opus Dei, bestowed on Alvaro del Portillo. Don Alvaro, as he came to be known, was for many years the founder' s closest associate as well as his successor and first Prelate of Opus Dei after it became a personal prelature— a foundational rock for this dynamic international Catholic group devoted to promoting sanctity in ordinary life. Written in anticipation of Bishop del Portillo' s September 2014 beatification— his official recognition by the Church as " blessed" and a stage on the way to his possible canonization as a saint— the book is a fact-filled biography set against the background of historic events like the Spanish Civil War and Vatican Council II. It depicts a person of powerful integrity and conviction who set aside a promising engineering career to follow the vision embodied in Opus Dei. Don Alvaro emerges in these pages as a tower of strength, reliability, and good humor in the face of a host of threats and challenges that might well have defeated a lesser man. John Coverdale, an attorney and historian, is the author of two other books detailing the early days of Opus Dei— Uncommon Faith, about St. Josemarí a and his companions during and shortly after the civil war in Spain, and Putting Down Roots, about Father Joseph Muzquiz, along with Alvaro del Portillo one of Opus Dei' s first priests, who played a key role in introducing it in the United States.