This is a guide designed for professionals who need to assess the literacy ability of adults. The three general categories of literacy skills which are distinguished include generic literacy skills, everyday skills, and job-related skills. Functional literacy has been defined in various ways, therefore, the assessment of it is very difficult. The purpose of literacy assessment must be established before selecting the appropriate instrument. The criteria to be considered are usability, validity, and reliability. The decisions to be made before a specific test or assessment approach are identified relate to the categories of literacy, the purpose for testing, the uses and users of test results, examinee characteristics and logistics. General guidelines for reviewing existing published or unpublished tests are examined. These include preliminary screening and technical quality review. Assessment of everyday literacy activities may be determined through the use of one of several published tests designed for this purpose. Assessment of on-the-job literacy is usually limited to tests of clerical ability. Appendices to the guide include suggested readings on definitions of functional literacy, published tests of basic writing and reading skills, and procedures for scoring writing samples. (DWH)