This photo shows the house in Dublin in which Frank Duff lived. Possessing a first-rate mind, Mr. Duff worked for years as a member of the Civil Service in Ireland in the Department of Finance. He invented a system of financial calculus when he was 21 years old that was later adopted by the Department and the Treasury Department of the British Government. In 1921 he founded the Legion of Mary, an apostolic organization that has spread throughout the world and now has over 6 million members.