Physical distance appears to act as a restraint on interaction at all levels of social organization. However, there is one specific problem connected with high-speed in teraction over great distance in the international system - that of time differences. In international travel the 'jet lag' causes fatigue and related phenomena. (The problem of a sudden change of climate associated with rapid North-South movements has not been studied to the same degree, but appears to be less serious.) In attempting to cir cumvent these unpleasant effects by interacting through telecommunication (moving information rather than moving people), one runs into a related problem - that of non-overlapping office hours. Informal data from several organizations with interna tional activities are cited as examples of how these problems are dealt with. Technologi cal and social 'solutions' to the problem of time differences are discussed. Several of these raise new problems, among them the possibility of an emerging 'time imperialism'- with dominant nations, organizations, and individuals imposing their own time cycles on their dependent individuals and groups - seems particularly ominous.
