In Chapter 3, we analyze the demand side of the market for dogs. We first consider some implications of the tension between treating dogs as property and their commonly perceived status as family members. We report on the increasing prevalence of dogs in U.S. households and review the survey evidence that shows that a large majority of households now consider dogs to be family members. We describe some of the factors and reasons that affect the demand for dogs in general, and the differences across socio-demographic groups. We consider whether pets are (economic) substitutes or complements for children. We address particularly economic explanations for potential inefficiencies (market failures) in the demand for dogs. We then consider demand for specific types or breeds of pet dogs, which can be explained partly by the theory of fads. Finally, we consider dog ownership in two circumstances: first, dog ownership by the homeless; second, the (perhaps temporary) increase in dog ownership during the COVID pandemic. We use microeconomic analysis of markets to help understand the surge in dog ownership induced by COVID and predict its long-term impacts.