This publication can be used as basic course in tracer methodology in the curricula of chemical engineering, engineering processing, and oil and gas reservoir engineering faculties at universities. It is also expected to be of wider interest for the further development of skills and confidence to carry out field work. The report will also be of interest to industrial managers and decision makers, who are generally educated in areas outside of nuclear applications. This book seeks to inform both specialist and non-specialist readers about the application and impact of radiotracer technology in modern industry.