Effective work groups do not develop overnight. Instead, they must evolve, over time, from the primitive collection stage at which they begin to a point where they become viable, cohesive social units. Everyone at some time or another has been a member of at least one task group from the time of its initial formation through and including much later stages of the group’s development. The recruiting techniques and sources utilized to attract potential members also create expectations having implications for subsequent motivation, group development and performance. Groups that are formed on the basis of personal friendships and informal contacts may meet their needs for warm bodies, but they will not necessarily turn out to be viable, high performance units in the long run. Teamwork reflects the group’s early task successes and the development of positive interpersonal relationships, which encourage the group and build its confidence.