This book has been specifically written to serve as a textbook of physiology for students at veterinary colleges, schools, and for veterinary technicians. Additionally, it will be of interest to individuals seeking information about domestic animals. The aim of the book is to provide a clear and concise account of the physiological functioning of various systems in domestic animals. When appropriate, examples from both human and non-domestic animals, such as rats and rabbits, have been used to illustrate key concepts. Physiology has evolved into a vast field of study, and this book covers the subject matter based on the most recent syllabus determined by the Veterinary Council of India for veterinary graduates. Additionally, the book addresses a wide range of challenges faced by veterinary and animal science students, providing a comprehensive yet representative description of these challenges.