This book is primarily intended for students who plan to pursue a career in the field of medicine. We describe in a simple way the usefulness of physics in understanding the functioning of various organic systems of the body, such as the eyes, ears, lungs, and heart. Although initially this book was written for students who already have basic knowledge of physics, we believe that a large part of it will be interesting and understandable for anyone interested in learning about the functioning of their body. The mathematics in the book are at the algebra level.