In general, historians seldom venture into predicting the future. Their discipline and training guides them toward attempting to reconstruct the past by relying on research, scrutinized facts, deliberation, and analysis. Other disciplines seem sometimes to disagree. That historians do not venture into predictions does not arise from a conservative orientation in their discipline, which may lead to a lack of enthusiasm for adventure; it comes from a philosophical attitude toward study of human society that points up the fact that the task of reconstructing the past, when data are obtainable, is a monumental task. Doing the same for events that have yet to happen can easily turn into futile attempts precisely because of lack of adequate data for analysis. On rare occasions, of course, major events in history have been predicted. World War II is a good example. However, observers missed other, equally significant events. The fall of the Soviet Union and the Iranian Revolution of 1979 are two examples.