People use the word strategy in a variety of different contexts. The term has connotations ranging from statesmanship to economic planning, and has become pervasive in the social sciences. We also talk about "problem solving strategies" and "corporate strategy" in a large business enterprise. The concept of strategy applies whenever a sequence of goal-oriented actions is based on large-scale and long-range planning. This monograph gives a systematic overview of the theory of strategies, a new area of enquiry developed over the past two decades by the author and his team. The projects described have clearly defined research objectives and are based on realistic assumptions about the environments in which