2nd edition, completely revised in line with the latest systematics. Based mainly on the collections of the Natural History Museum (BMNH) in London, the author has re-subjected the two families to a complete taxonomic (sensu Linnaeus) revision, taking note of the latest revisions and publications since 1983. This revised edition, with nearly completely new text, incorporates digital re-scanning of the original film images made by the author in 1983, as well as images he made for other authors, including Racheli (1992) and Möhn (1999). The author has introduced an up-to-date synonymy based on demonstrable scientific evaluation of polymorphism due to seasonal, altitudinal and sexual factors, as well as to the hitherto poorly understood phenomenon of the cline. The work also contains serious discussions of the History and Philosophy of the Science of Taxonomy and the fundamental mechanisms of genetics in relation to the Lepidoptera of the world.