This introduction to bilingualism is designed with the undergraduates especially in mind. Since its primary concern is with the bilingual individual, it does assume some knowledge of the basic principles of linguistics. Less detail is accorded to societal bilingualism since the premise is that sociological aspects of bilingualism should be approached only once an awareness of the individual linguistic phenomenon has been understood. The work draws together much of the variegated information published in different sources since the early fifties. Major issues covered are: (1) definitions and typologies, (2) interference and code-switching, (3) measurement of bilingualism, (4) theoretical considerations, and (5) problems of the bilingual speaker. (Author/JK)