Newell & Simon’s 1972 book Human Problem Solving continues to influence theories of problem solving. Their theory provides a general framework for specifying how the structure of the problem, strategies, and different sources of knowledge influence progress from the initial state to the goal state. In contrast, discovering solutions for problems studied by Gestalt psychologists typically require a perceptual reorganization to identify the correct relations among the components of the problem. A rapid shift to a correct organization is referred to as ‘insight’. Solving mathematics and scientific problems requires utilizing information learned in the classroom. This information is organized into clusters of knowledge that are typically called ‘schema’. Design problems are usually ill-structured in which the initial, goal, and intermediate states are incompletely specified. There are no right or wrong answers, only better and worse ones. The size and complexity of the problems require decomposition into smaller problems or modules.