Natural Killer Cells explains the importance of killer cells and how they are produced. It mentions that the most likely explanation for killer cell production is that they serve as a complementary system for T cells as a primary defense against viruses. However, these cells defend against certain viruses only, such as herpes viruses and influenza viruses. The book also explains the primary functions of killer cells, and it discusses how these cells help recognize damaged tissues, limit further damage to tissues, and regenerate damaged tissues. It discusses how these cells mature and develop, and it covers the different isolation, culture, and propagation methods of these cells. Furthermore, it focuses on the different killer cells that are present in various parts of the human body. The book concludes by explaining that natural killer cells are utilized for clinical therapy of malignancies, and that they have led to positive outcomes in the field of biology and medicine.