Book excerpt: Dr. Gunnar Borg introduced the field of perceived exertion in the 1950s. His ratings of perceived exertion (RPE) scale is used worldwide by professionals in medicine, exercise physiology, psychology, cardiology, ergonomy, and sports. Now, Dr. Borg presents the definitive source for using the latest RPE and CR10 scales correctly. Borg's Perceived Exertion and Pain Scalesbegins with an overview and history to introduce readers to the field of perceived exertion. The book then covers principles of scaling and applications of both the RPE and the CR10 scaling methods. This user-friendly, informative, and readable text -discusses the fundamental bases of perceived exertion, -presents information on uses and misuses of the scales, and -provides guidance and direction on how and when to measure subjective somatic symptoms. A special appendix in the back of the book includes tear-out cards containing three RPE scales and three CR10 scales. A scale and instructions for how the scale is used are printed on each two-sided card. Borg's Perceived Exertion and Pain Scalesis the complete theoretical and methodological guide to the field of human perception.