The lone individual—the single man or woman who has no connection to
other men and women—is an extraordinarily rare human being. Homo sapiens
is capable of surviving alone, and the recluse, ascetic, and prisoner in solitary con-
finement can forge a life on their own. But few humans seek or enjoy the
challenges of solitude. Most people prefer to live in groups. Virtually all the activities
of our lives—working, learning, worshiping, relaxing, playing, and even
sleeping—occur in groups rather than isolated from others. Most people belong
to many different groups, so the number of groups in the world probably reaches
well beyond six billion. The world is literally teeming with groups.
For centuries, sages and scholars have been fascinated by groups—by the way
they form, change over time, dissipate unexpectedly, achieve great goals, and
sometimes commit great wrongs. Yet groups remain something of a mystery—
unstudied at best, misunderstood at worst. Here we unravel some of their mysteries
by examining their basic nature, their processes, and their impact on their
members. We begin our task by asking some questions: What is a group? What
are the characteristics of groups that most interest us? What kinds of group processes
do we want to study? What do we mean by group dynamics? What assumptions
do we embrace as we describe, analyze, and compare the various groups
that populate the planet? What approach do we take to the study of group