This book deals specifically with the historical basis for use of terms in race, gender, ethnicity, sex and sexual orientation. It brings much needed clarity to the debate by identifying the ethical issues as well as the technical challenges inherent in measuring these elusive concepts. The author expands on her work begun in Gender, Ethnicity, and Health Research by paralleling the evolution of racial and sexual categories with the development of health research. In addition, the book provides a salient guide to assessment tools currently used in measuring racial and sexual constructs, identity, and experience.