This is "the book" in my very humble opinion, for understanding the role of the immune system and how it relates to health and disease - not only in regards to animals, but people and the environment as well. From the basics of the skin barrier to delving into the complement system and how antibodies and antigens work in the body, it was an incredible guidebook. It was not a necessary read for my university studies, but a supplemental one that I do not regret purchasing. I thoroughly enjoyed this textbook. I found the study of the immune system to be fascinating. I definitely credit this book in capturing my interest regarding immunology and disease. Amazing read and highly recommended.