These are just a few representative applications of the synergistic use of computer and robotic technology assisting the orthopaedic surgeon. While the individual systems are certain to change over time, the basic principles of correlating radiographic and anatomic data through a registration process, and displaying additional instrument or implant information through smart tools and surgical navigation are certain to become an increasingly important aspect of joint arthroplasty, deformity correction, and spinal and trauma surgery. Only the orthopaedic surgeon who clearly understands the goals, applications, and limitations of these systems can decide which are appropriate for his patients, his hospital, and his practice. Determining the cost and time benefits, both before and after an obligatory "learning curve" requires a complex interaction of capital investments, time savings, and outcome research on both safety and efficacy issues. The orthopaedist who understands and applies these technologies will help his patients to achieve the best possible care. Excellent resources in the literature on this topic include the September, 1998, issue of Clinical Orthopaedics and Related Research, a symposium on "Computer-Assisted Orthopaedic Surgery: Medical Robots and Image Guided Surgery"; Guest editor, Anthony M. DiGioia, III, MD. Also, the January, 2000, issue of Operative Techniques in Orthopaedics, "Medical Robotics and Computer-Assisted Orthopaedic Surgery. Guest editors: Anthony M. DiGioia, III, M.D. and Branislav Jaramaz, Ph.D. Additional Internet based information is available from the Journal of Computer Aided Surgery (formerly: Journal of Image Guided Surgery), at http://journals.wiley.com/.