Because of the biological similarities between many animals and humans, scientists can learn about diseases, and find out how humans might react to medicines, cosmetics, chemicals, and other products by testing them on animals first. According to the Humane Society of the United States, more than twenty-five million animals are used in research, testing, and education each year. Readers learn about the various philosophies on animal testing, what tests are used, and how they are performed. The book presents the pros and cons of animal testing and some of the alternative methods to animal testing that scientists are developing today.