Book excerpt: The use of stable isotopes in nutritional studies is now widespread, and the technique is becoming increasingly popular. Practical applications are numerous and include:calcium and iron absorption studiesstudies looking at the impacts of diet, physical activity, aging, and medical therapy and supplementation on nutrient metabolismthe measurement of energy cost of pregnancystudies on the causes of growth faltering in infantsinvestigations into childhood and adult obesity.This book is designed as a laboratory handbook of methods used to perform stable isotope studies in humans. It covers basic principles, dosage information, sample preparation procedures, analytical instrumentation, and necessary mathematical methods and provides the fundamentals to enable researchers to evaluate and establish stable isotope methods in their own laboratories.