"The Essay on Man in modern editions is a single poem, arranged in four “Epistles.” But in the beginning, each epistle was published separately, the first on February 20 , the second on March 29, the third on May 17, and the fourth in the next year, on January 24, 1734. In May of 1733 the first three epistles were issued as a stitched together pamphlet, but the pamphlet was made up of separately issued copies of the three epistles. It was not until May 2, 1734, that all four parts were printed together as a single poem.", Alexander Pope; a bibliography, by Reginald Harvey Griffith (1922), Volume I, part I, p.211.
This transcription is of an edition published in 1751.