This major new reference for study and research in human abilities takes an innovative approach not found in any other book in the field. Part One offers a revaluation of ability theory by the editors, and strong individual contributions by those representing markedly different approaches to the measurement of intelligence. Part Two contains reviews of various regional and national empirical studies in Britain, Norway, Turkey, Australia, China, Japan, Southern Africa, and the United States. Part Three concentrates on contexts where the limits of human assessment by psychological tests are defined: in minority native groups in North America, in migrants in Britain, in lower caste enclaves in India, and among Australian Aborigines. Written by long-term residents of the regions represented, the chapters bring with them a wealth of new material that has been ignored in western formulation of theory and practice. The editors have issued one of the best-formed, most sustained scientific challenges to the conventional wisdom of human assessment to appear for decades.