Career
Mason specialized in collecting and studying proofs and essays related to United States postal history, and wrote extensively on the subject. His books include: Essays for United States Postage Stamps, published in 1911, The Proofs and Essays for United States. Envelopes, also in 1911, and More Essays for United States Postage Stamps, in 1912. Mason’s listings of proofs and essays were the basis for their listing in Scott United States. Specialized Catalogue of Stamps.
At the time Mason performed his studies and wrote, it was illegal in the United States to publish illustrations of United States postage stamp material.
Only ten copies of Mason’s books, with photographs interleaved by the New England Stamp Company, were especially printed. Copies of these interleaved books are located at the Collectors Club of New York and at the Smithsonian Institution, in the library of the National Postal Museum.
