This research synthesis identifies a number of important concepts regarding the teaching of problem solving skills to students in grades K-12. Studies investigated what problem solving skills are and whether they can be taught, as well as how problem solving can be organized in the curriculum and how it should be taught. Major findings from the research base include: (1) Students can learn to be better problem solvers through exposure to focused instruction; (2) Direct teaching of problem solving strategies improves problem solving skills in students; (3) Problem solving competence requires a knowledge base in the content area in which problems are posed; (4) Problem solving objectives are best taught through integration with existing curricula; (5) Transfer and use of problem solving strategies appears more likely when problems used in instruction are like those that will be routinely encountered later; (6) Successful instruction requires attention to student motivation, content knowledge, and problem solving skills and strategies; and (7) Effective instructional practices identified in this synthesis are consistent with the findings derived from the effective schooling research base. (JD)