This book is a detailed and comprehensive medium helping students and researchers to understand the theory and concepts of biomarkers. Biomarkers or biological markers are used as an indicator of a person's health state or condition by scientists or medical professionals. If a biomarker can detect basic symptoms of a disease, differentiate between similar diseases, identify the stage of advancement, work on an easy-to-perform and inexpensive system of diagnosis and is easily accessible to the body; then it is considered to be the ideal biomarker.