German Catholic theologian and historian of dogma, born in Pursruck (Bavaria) on October 22, 1876, and died in Tübingen on 1 April 1966. Writer of great depth in the theological and spiritual renewal of the pre-Vatican II Catholicism, highlighted by know present in language simple and affordable to the general public the depth and the actuality of Christianity. Ordained in 1900, Adam continued his studies in Munich to then engage in tasks of teaching and pastoral work in Strasbourg. In 1919 he/she was appointed Professor of dogmatic theology at the University of Tübingen, where he/she remained until his retirement immediately after the second World War (1949). Here he/she published his best works, which enjoyed a favourable reception, and that became an essential classic of Catholic Theology of the twentieth century. His masterpiece is the essence of Catholicism (1924), which, translated into eleven languages, earned universal recognition; It exhibits a deep theological vision of the Church, emphasizing the doctrine of the mystical body. In 1926 he/she published Christ our brother, the first part of a trilogy on Jesus Christ, which was completed by Jesus Christ (1933) and the Christ of faith (1954, his last great work). In Una Sancta (1948) he/she faced, and vigorously supported the theme of ecumenism from the Catholic point of view. His sense of history and his deep piety added a dimension of approach that is not always in works of theological disclosure to his writings. Their theology caused some concern in the Vatican, but he/she knew how to cope so that none of them should be put into question.