Between 950 and 1950, European states experienced four short intervals of rapid social, political and economic change. Each such period followed the introduction of a macroinvention in information and communication technology. Here these two sets of events are linked by a rational theory of revolution in which the optimal system for producing the information to allocate a society’s resources depends on the relative importance of fixed costs and network effects. Variations in these parameters can trigger four types of revolution — contractual, consensual, preemptive and prescriptive — each of which captures the essential features of one of the historical periods of change.