It's called a ''network organization''-a lean, highly flexible, ''disaggregated' company that operates through a cluster of down-sized, focused business units. Market mechanisms, rather than layers of mid-level decision makers, drive strategy, and senior managers stand ready to outsource any function that does not meet competitive tests. This form of organization, which the authors identified and labeled in the early 1980s, is spreading across industries, giving a sharper edge to competitiveness. Now, Snow, Miles, and Coleman trace the recent history of the network and project its impact into the 21st century. Three forms of network structure have emerged: internal (as exemplified by General Motors' components divisions), stable (such as used by BMW), and dynamic (shown by Lewis Galoob Toys). More important, the spread of network organizations is creating new agendas for both managers and business schools. For current managers, it means playing previously undefined roles related to the design, coordination, and caretaking of the clustered units. For management schools worldwide, it means a basic reconsideration of how tomorrow's managers are trained.