A literature review examined the relationship of adults' verbal and mathematical literacy to employers' investments in training, employee wages, unemployment probabilities, unemployment duration, technological change, productivity, and economic growth. Most of the publications analyzed dealt with the United States. The analysis revealed that adults' basic literacy skills, which are usually acquired in school, do indeed affect the wealth of individuals and nations both directly and indirectly. The study also established that, although many workers receive some training from their employers, employers tend to invest most heavily in training their best educated/trained employees and concentrate training on craft, sales, managerial, and professional/technical skills. Employer-sponsored training has been found to complement rather than substitute for good foundation skills and to increase employees' productivity and earnings more than training in postsecondary institutions does. Employer-sponsored training also reduces job turnover, layoffs, and duration of periods of unemployment. Determining whether employers or economic sectors in a nation underinvest or overinvest in training depends on estimates of the rates of return to training; however, in the United States measurement of training costs is too poor to yield estimates of returns sufficiently narrow to serve as a basis for policy decisions. (Contains 33 references.) (MN)