"He's just playing" - one of the slogans in the dog community par excellence. But do dogs really want that? And do they actually need playful interactions with each other, with humans, or on their own? What constitutes play, how to recognize it, the different forms of play that exist, the positive aspects of play behavior, and the difference between fulfilling activities and obsessive behavior with addictive potential are explained clearly and understandably by the author team in this volume of the "Understanding Dog Behavior" series.