This document summarizes the research done on calculators and calculator use. It is noted that calculators are now seen as acceptable, with fears about use in school currently infrequent, and the role of such devices much more evident than 6 years ago. The first two sections of this material summarize data on use and availability. It is noted that within the 75 studies used in this analysis, 35% provide evidence that students score higher when calculators are used, 44% indicate no significant difference, 19% report mixed findings, and only 3% report calculator use led to lower student scores. This document next covers problem solving and calculator use in the following content areas: counting, basic facts, addition and subtraction, multiplication and division, decimals, estimation, and trigonometry. Evidence on testing, curriculum concerns, and attitudes conclude the review. (MP)