A career in the U.S. Marine Corps and ordination to the Catholic priesthood are commitments to service, but it is rare one would not only have both these callings and be a widower and father as well. Timothy M. Gahan is such a man. Raised in a large Irish Catholic military family, he served in the Vietnam War as a helicopter machine gunner and was later commissioned in the Corps. Leatherneck to Roman Collar describes the unusual life and times of a 27-year USMC veteran and family man who became a parish priest as told by one of his sisters. It is a compelling story of meeting challenges, devotion, overcoming obstacles, sacrifice, happiness and love of country, family and God.