The needs of adult college students (25 years old or older) and support services that could promote achievement and retention of these nontraditional students are considered, based on the literature on current research. Of concern are students enrolled in credit courses at two-year or four-year institutions. Attention is directed to four kinds of needs that should be addressed in order for learning to occur: general understanding, basic skills, self-knowledge, and awareness of the mode of learning desired to achieve one's goals (e.g., self-directed, collaborative modes). Adult students' nonacademic needs have also been addressed in studies. Student personnel workers who design support programs are becoming aware of the unique characteristics and needs of adult students, who are returning to college in record numbers. The literature indicates that adult students who participate in support programs sometimes attain higher academic achievement and retention rates than those not involved in such programs. Additional topics addressed in the literature review include: types of barriers to adult students' participation in higher education, skills possessed by adults who have "learned how to learn," and ways to serve adult students through support groups. (SW)