This essay begins with a brief history of calculator development and presents some lessons learned about using calculators in work dating back to the 1970s. A position statement on the appropriate use of calculator technology is presented along with a discussion of some of the controversial issues that have arisen as a consequence of the use of calculators. The importance of a balanced approach to the teaching and learning of mathematics that use both technology and paper-and-pencil techniques is presented. Some research evidence about calculator use is given. The status of the use of calculators in the teaching and learning of mathematics outside the United States, and recent advances in calculator technology are discussed. (MM)