The present volume is a corpus-based study of the occurrence, variation, and change in the use of English adjective pairs in -ic and -ical over several centuries. The study involves the analysis of large, multi-million-word corpora representing the English language at various stages. It examines the nature of competition between the two affixes: what kind of rivalry existed, what kinds of words entered into competition, and in what ways the rivalry was resolved. The book presents close studies of six notably differentiated -ic/-ical adjective pairs, namely classic/classical, comic/comical, economic/economical, electric/electrical, historic/historical, and magic/magical, as well as commentaries on some 40 other -ic/-ical pairs, which manifest different types of shifts in use through history.