This document discusses interpersonal groups and types of groups. It defines a group as two or more individuals who have come together to achieve objectives. Reasons for joining groups include security, socialization, status, accomplishing tasks, self-esteem, decision-making, affiliation, communication, and power. There are two types of groups: formal groups created by an organization and informal groups created by members. The document also discusses group structure, cohesiveness, work teams, and issues in managing work teams such as performance, diversity, and social loafing.