This is the most comprehensive survey ever published of auxiliary verb constructions, as in 'he could have been going to drink it' and 'she does eat cheese'. Drawing on a database of over 800 languages Dr Anderson examines their morphosyntactic forms and semantic roles. He investigates and explains the historical changes leading to the cross-linguistic diversity of inflectional patterns, and he presents his results within a new typological framework. The book's impressive range includes data on variation within and across languages and language families. In addition to examining languages in Africa, Europe, and Asia the author presents analyses of languages in Australasia and the Pacific and in North, South, and Meso-America. In doing so he reveals much that is new about the language families of the world and makes an important contribution to the understanding of their nature and evolution. His book will interest scholars and researchers in language typology, historical and comparative linguistics, syntax, and morphology.