In Chapter 1, a definition for problem is introduced, along with a model of the problem cycle, which is used to conceptualize the relationship between normal cognition, problem finding and problem solving. Initial experimental efforts to explore problem finding are discussed. In Chapter 2, previous work on problem finding and problem solving is reviewed. The few existing accounts of the stages of problem solving are surveyed, and the older literature on different kinds of problems and how they are solved is reviewed in detail. Chapter 3 builds upon the first two chapters by introducing a new taxonomy of problems, highlighting four dimensions that differentiate problem types and explaining each type at length. Chapter 4 describes an experiment developed to test the idea that problems can be organized along the lines of the taxonomy introduced in Chapter 3, and that these differences determine how they try to solve a specific instance of a problem. A simple game is developed and behaviors in the game are tracked, confirming the hypothesis that different problem types are solved in different ways, that are specific to the type of information available to the problem solver. The last chapter summarizes the dissertation and describes avenues for future research.