Mass attended Hempstead (N.Y.) High School, where he was president of his class and on the baseball, tennis, and track teams. He graduated as an honor student. At Princeton he majored in politics and graduated with second-group honors. He was a member of the Interclub Committee and Court Club president.

After Princeton, Mass graduated from Columbia Law School with a bachelor of laws degree and then served as a legal assistant to the district attorney in New York, Thomas E. Dewey, in 1940. He was admitted to the New York State Bar the same year. In 1941 he joined the FBI as a special agent and served in that capacity until his retirement in 1967. He received the juris doctor degree from Columbia in 1969.

Mass loved baseball and had interests in philately, historic documents, and old newspapers. He was active in tennis and golf.

The class extends its sympathy and remembrances to his friends and family.

Undergraduate Class of 1937