This report is one of a series of booklets prepared especially for extension workers and others engaged in development programs within or outside universities. It discusses what is meant by extension when applied to universities and reviews the various forms of extension (preentry courses, part-time courses, para-university courses, post-university programs, and professional studies). It examines briefly some of the possible structures that can enable a university to engage in extension and suggests that each university has a mission to fulfill. Self-study questions are provided throughout the booklet. (KC)