The book covers the many ways humans benefit from interactions with other living species. By studying animals of all kinds and sizes, from microbial organisms to elephants and whales, we can learn about their adaptations to extreme conditions on planet Earth, about the evolutionary development of specialized capabilities, and about their ways to defend themselves against predators and diseases. We discuss the strengths and weaknesses of Homo Sapiens, and how the study of animals can make us stronger and healthier. To increase our knowledge of genetics, molecular and cell biology, physiology and medicine, we need to study model organisms. To cure human disease, we can learn from animals how they have evolved ways to protect themselves. To improve our human performance, we can study the animal kingdom's top performers and possibly learn from their successes. Finally, we review genetic engineering techniques that can translate our existing and future animal connections into benefits for human health and performance.