This booklet presents techniques used by the Office of Cancer Communications of the National Cancer Institute for pretesting health education materials for professional, patient, and public audiences. The approaches and experiences of other health organizations are also reviewed. Described are principles of pretesting and how pretesting can be incorporated into materials development. Some of the methods considered include questionnaires and individual and group interviews. Also discussed are resources needed to conduct pretesting research. A fundamental premise of the booklet is that health communication programs must be based on an understanding of the needs and perceptions of their target audiences. A glossary of pretesting terms and a bibliography are appended. (APM)