{Excerpt} Cooperative work by a team can produce remarkable results. The challenge is to move from the realm of the possible to the realm of practice. Groups that range from two persons to many are a very big part of social life (indeed, of human experience). They can be significant sites of socialization and learning, places in which beneficial relationships form and grow, and settings where knowledge and wisdom flourish. Because they also offer individuals the opportunity to work together on joint tasks and develop more complex and larger-scale activities (projects), groups can be highly rewarding to their members, organizations, and society at large. On the other hand, the socialization they offer can constrict or even oppress members. Groups can also become environments that exacerbate interpersonal conflict, for example if one individual dominates or tries to “score points.” In addition, the boundaries that are drawn around them can exclude others—sometimes to their detriment—and create intergroup conflict. What is more, belonging to a group often warps the judgments of members: pressure to conform can lead to “groupthink” or poor decision making. Other, well-nigh mundane shortcomings include diffusion of responsibility; excessive diversity of views, goals, and loyalties; and the tendency to “solve” (but not analyze) problems. These potential strengths, weaknesses, opportunities, and threats make groups an essential focus for research, exploration, and action, for instance regarding group development (teamwork) in organizations.