A discussion of the immersion approach to second language instruction contains: a description of the approach and its goals; a brief history of its introduction into public schools; a description of the most common immersion program designs (early total, early partial, middle or delayed, and late); a review of available information on program results concerning effects on English skills, second language skills, and the learning of subject content material, achievement as related to IQ and learning disabilities, differences between partial and total immersion programs, and outcomes from late immersion; an examination of the benefits of early immersion; a description of the distribution of programs in the United States and of the Milwaukee, Wisconsin public schools program; and an analysis of the theoretical foundations of the approach and links to other second language instructional approaches. (MSE)