This paper examines knowledge of studying--knowing how and when to apply study strategies. Study strategies may be classified into three categories: memory strategies, comprehension strategies, and problem-solving strategies. Memory-study strategies help students remember what they study. Five attributes often characterize memory strategies: meaningfulness, organization, association, visualization, and attention. Some memory strategies include rhymes, patterns, acronyms, acrostics, the link system, the loci system, and the peg system. Comprehension strategies help students understand what they study. Activities in comprehension strategies include identifying important information (e.g., underlining main ideas or taking note of headings); paraphrasing and summarizing important information; generating examples and questions; outlining; reorganizing notes; and elaborating. One of the most well-known comprehension strategies is Francis Robinson's SQ3R method. Problem-solving study strategies help students solve problems, innovate, and invent. A number of writers have offered techniques for solving problems. However, a sound rationale underlying the processes of problem solving has not yet emerged. Strategies that are especially useful for solving well-defined problems usually focus on two activities: generating plausible alternative solutions and systematically testing these proposed solutions. (Author/RM)