This document defines social groups and discusses their characteristics and types. Social groups consist of individuals who interact and share common goals, values, and identities. Members join groups to fulfill personal needs like companionship, security, status, and leadership opportunities. Groups establish norms of behavior through rituals, uniforms, and language. The main types of groups discussed are primary groups which are small and intimate, secondary groups which are larger and less personal, voluntary groups which are joined willingly, and involuntary groups where membership is forced.