Lawyer, author, and authority on U.S. tax laws. Jack Mertens entered Cornell University in 1915. In January, 1918, he enlisted in the U.S. Army. After attending Officers Training School at Camp Upton, he was shipped to France with the 305 Infantry. He ultimately was transferred to the 111th Infantry Regiment, Company B, 28th Division with the American Expeditionary Forces and was sent to Camiers where he received special machine gun training. He became a sergent in May and a 2nd lieutenant in August, 1918. He participated in the Meuse-Argonne offensive, at Chateau Thierry and St. Mihiel. He was discharged in December 1918 and returned to the U.S. as a machine gun instructor. He graduated from Cornell in 1920 and then received a law degree from Columbia University.