MacMahon's partition analysis XII: Plane partitions

MacMahon developed partition analysis as a calculational and analytic method to produce the generating function for plane partitions. His efforts did not turn out as he had hoped, and he had to spend nearly twenty years finding an alternative treatment. This paper provides a detailed account of our retrieval of MacMahon's original project. One of the key results obtained with partition analysis is an extension of a theorem of Gansner which generalizes Stanley's famous trace theorem.