This book is a standard reference for all priests and laymen who make the study of theology an important part of their lifetime reading. It is precise, concise, and very thorough. It was written by the Secretary of the CDF under Pius XII who was an important early 20th century orthodox Catholic theologian. Pietro Parente (16 February 1891 in Casalnuovo Monterotaro, Italy – 29 December 1986 in Vatican City) was a long-serving theologian in the Holy Office of the Roman Catholic Church, and was made a cardinal on 26 June 1967. At his peak he was regarded as one of the foremost Italian theologians. This book is specifically designed as a bridge for educated lay people and clergy who need a summary of Church doctrine that is concise, clear, and concise without having to get lost in complicated scholastic debates.