Bachelor of Science, University Pittsburgh, 1942. Master of Science in Chemistry, University Pittsburgh, 1952.
Cohn was particularly interested in the siege mail of the Franco-German War of 1870-1871 although his collecting interests were previously more widespread. Ernst Cohn authored a number of books during his philatelic career, including: Die “Papillons” von Metz (1976), The Flight of the “Ville d’Orleans (1978), Ordinary Mail by Diplomatic Means (1995), Unusual Mail in Occupied France 1870–1871 (2000), and A Book of Postal History (1988) which contained many of his articles he had previously written for The American Philatelist. At the American Philatelic Society, he served a number of posts, including representative to the FIP Postal History Commission and on the Postal History Committee.\r\nAt the Postal History Society he held a number of posts including president and associate editors
Cohn was a member of the most important philatelic societies in the United States, France, Belgium and the United Kingdom.
Married Margaret Miller, July 8, 1949 (divorced February 1981). Married Doris Brohm, March 31, 1981.