This document summarizes Malcolm Knowles' theory of andragogy, or adult learning. It outlines six key characteristics of adult learners: they are autonomous, self-directed learners who draw on life experiences; they are goal-oriented and want learning to be relevant; and they are practical and need to respectfully voice their opinions. The document also identifies six factors that motivate adult learning: social relationships, external expectations, social welfare, personal advancement, escape or stimulation, and cognitive interest.