Is it heredity or environment that shapes the dog? Researchers J. P. Scott and John L. Fuller, authors of Genetics and Social Behavior of the Dog, bred and cross-bred dogs in their quest to understand human heredity and behavior. Their research yielded a gold mine of data that Pfaffenberger turned into practical information for dog breeders and trainers. Learn about the critical stages of puppy development, how breed differences make dogs suitable for specialized work, and how to breed and socialize temperamentally sound dogs. Reprint of a 1963 classic.