Multiple (or extended) exponence is the occurrence of multiple realizations of a single morphosemantic feature, bundle of features, or derivational category within a word. This book provides data and direction to the discussion of ME, which has gone in a variety of directions and suffers from lack of evidence. Alice Harris addresses the question of why ME is of interest to linguists and traces the discussion of this concept in the linguistic literature. The four most commonly encountered types of ME are characterized, with copious examples from a broad variety of languages; these types form the basis for discussion of the processing of ME, the acquisition of ME, the historical development of ME, and analysis of ME. The book addresses some of the most important questions involving ME, including why it exists at all.