In the world of medicine, the term immunology is an expansive and complex field within the discipline of anatomy. This branch of the medical sciences focuses on how the body's immune system works and interacts with other systems. The immune system is a network of cells, tissues, and organs whose main purpose is to protect the body from foreign substances. This system protects the body from disease and infections. This field of medicine is also responsible for the development of vaccines that humans use to protect themselves from such diseases. During my time working in the immunology sphere, I have had the opportunity to interact with several patients who come to me with different complaints and symptoms that may be related to some kind of immunological abnormality. I have also had to deal with patients who may have been exposed to some kind of infectious agent that could put their health at risk. That is why having an understanding of immunology is important for the general population. It is for this reason that I have written this book in an easy-to- digest format so that you can have a better understanding of the concepts behind immune function and disease. This book is based on my research as a doctor and biologist focusing on immunology and it offers a general overview of the different topics that are related to this discipline. This book provides information about the basics of immunology, the immunity system, and ways to prevent sickness. Some of the topics that are covered in this book include the process of immune response, the different types of white blood cells, the different types of antibodies and how they work, and many others. My name is Massoud Abbas, and this book is my way of giving back to society by sharing knowledge that I acquired while working and studying in this field.