An ongoing challenge when writing about the interaction of animal health, behavior, and the human-animal bond  is that the phrase has gained so many different definitions over the years. When I write or speak about the bond, I’m referring to ability of humans and animals to affect each other’s behavior and physiology for good or ill.  It’s not just a warm fuzzy feeling; it’s a bio- and neurochemical reality. Some bonds may benefit people more than animals. Others may benefit animals more than the people. In addition to the nature of the bond varying, so may its strength. Equally intriguing, humans and animals may affect each other’s physiology without the other being aware of this phenomenon. All of the articles in this section and indeed on the whole site are based on that awareness.