In 1940 he published his first book "Médecine de la Personne" (trans. "The Healing of Persons"), which was dedicated to Frank Buchman, the founder of the Oxford Group, wherein he advocates that man is more than just body and a mind, he is also a spiritual being. This combination is what makes man a person. Therefore, it is impossible to know and treat him if one disregards his deepest reality. After the success of "Médecine de la Personne" he became a prolific writer of books dealing with the subject. Although he did not have any formal training in psychiatry or theology, his writing has influenced a generation of medical and religious professionals the world over. His books would eventually be translated into 13 languages.