People began writing about stamps almost as soon as they began collecting them. The first stamp magazines, really little more than dealer price lists with articles, were issued before 1840 and by the 1890s the London Philatelist, the precursor journal of the Royal Society of London, was actively publishing monthly scholarly philatelic articles. By 1900, there had been hundreds of books published, though throughout the long tradition of philatelic publishing it has been periodicals,far more than books, that have had the most activity.The earliest period of philatelic literature is interesting for the vibrancy of the writing and for understanding which concerns of philatelists have changed and which have not. There was great emphasis in early literature on spurious stamps but that term was more broadly defined than it is today. The late 1890s had the great Colonies Explosion in stamp issues. Check your catalogs-thousands of stamps in long value sets from the French Colonies, British Colonies, Portuguese Colonies, and Spanish Colonies stamps were issued from 1890-1905. Mainstream collectors at the time were furious and felt, I think accurately, that the stamps were issued to take advantage of collectors and that such issues would damage the hobby in the long term (philatelic writing has a long tradition of Cassandras- every generation of collectors has predicted that it will be the last). The writing was colorful and is well worth your time to peruse.
Several years ago we donated several hundred large cartons of old philatelic books and periodicals to the American Philatelic research library. Before we did, we scanned a few of the more interesting articles that were out of copyright and put them up at the Apfelbaum Philatelic Library . They are fun to read when you have the time.