This book is written as per the competency-based medical education (CBME) guidelines for the Indian medical graduates. It covers essay type and short-answer questions. Important notes and recent advances have been added. This book fills the niche to provide basic information to an undergraduate in a nutshell. The text provides all the basic information student needs to know. Key words are shown in a bold font so that the student can rapidly go through the book just before the examination. The authors have incorporated many illustrations, tables, text boxes and flowcharts. These can serve as a source of rapid revision of physiology for both undergraduate and postgraduate medical students. It would also be useful for postgraduate entrance examination. The authors emphasize that this is not intended as a textbook of physiology but a supplement for quick revision of the subject before examination.