This book explores the reasons why adult ESL learners drop out of their language classes and suggests explicit strategies for keeping students engaged. The most effective strategies may be personal rather than technical or curricular. Based on a study of a group of Mexican immigrants to the US, the author proposes that "superación" or 'self-actualization' is crucial to understanding the relative success of adult ESL learners. Learners' decisions to drop out were not hasty or superficial but were based on a commonsense assessment concerning how the class might improve the quality of their lives. Those involved in delivering ESL to adult learners should stress the tangible, practical advantages that accrue with learning English, and at the same time strive to make instruction relevant.