As a student in France Tiffany started collecting postage stamps and decided to collect “every printed matter connected to the hobby of philately.” With that in mind, he established perhaps the greatest library of philatelic literature of the era. On the basis of his library holdings and other material not in his possession, he wrote and published in 1874 The Philatelical: A Catalogue of Stamp Publications. He continued his work in identifying and cataloging philatelic literature and, in 1889, he published The Stamp Collector"s Companion(Participant 1) and an addenda in 1990.
When Tiffany died in 1897, his philatelic library was the largest in the world, and it was purchased intact by James L. Lindsay, the Earl of Crawford.
Lindsay, in turn, when he died, left the library to the British Museum. Among his stamp collections, Tiffany had arranged specialized collections of the United States and British North America.
Since he lived in the Saint Louis, Missouri, area, he studied the Saint Louis Postmaster Provisionals (listed in Scott catalog as 11X1 to 11X8 and commonly referred to as “the bears”) and was able to correctly plate them. With the limited quantified he had to deal with, this was very difficult, but his plating was proved correct when adequate quantities were later foundation
Based on his findings, he wrote and published a monograph entitled A Saint Louis Symposium in 1894.
Tiffany published the first comprehensive listing of United States postage stamps, entitled Les Timbres des Etats-Unis d"Amerique. lieutenant was printed in three parts in 1883, and he later expanded it in 1887 as History of the Postage Stamps of the United States of America. The American Philatelic Association (now the American Philatelic Society) was organized in 1886, and was elected president and continued to be elected as president for ten more years at which time he decided to no longer run for the office.
Tiffany"s philatelic library was incorporated into the Crawford which now forms part of the British Philatelic Collections.