In ancient India, learning spanned four quarters of one?s life. Learning was sought from the teacher, from one?s individual effort, from fellow students and in the last quarter, from the school of life itself. This book belongs to the third quarter for students of Ayurveda regardless of their background in medicine, science, or humanities. Apart from topics in the eight branches of Ayurveda, the book also deals with ?yurvedic Biology which seeks to study the concepts and procedures of Ayurveda with the tools of modern biology. M S Valiathan is a National Research Professor of the Government of India. He is a medical graduate from the University of Kerala and completed his postgraduate training in general surgery from the University of Liverpool and other hospitals in the UK. He did his specialisation in cardiac surgery from the Johns Hopkins and Georgetown University Hospitals in the US. He was a cardiac surgeon for over three decades. His shift to Ayurvedic studies resulted in the publication of three volumes on Caraka, Su?ruta and V?gbha?a, and an Introduction to ?yurveda. The Department of Science and Technology set up a Task Force in Ayurvedic Biology under his chairmanship to promote research in the nascent discipline.