Is it possible for humans to discover the key to happiness through a bigger-than-life, bad-boy dog? Just ask the Grogans.

John and Jenny were just beginning their life together. They were young and in love, with not a care in the world. Then they brought home Marley, a wiggly yellow furball of a puppy. Life would never be the same.

Marley grew into a barreling, ninety-seven-pound streamroller of a Labrador retriever. He crashed through screen doors, gouged through drywall, and stole women's undergarments. Obedience school did no good -- Marley was expelled.

But just as Marley joyfully refused any limits on his behavior, his love and loyalty were boundless, too. Marley remained a model of devotion, even when his family was at its wit's end. Unconditional love, they would learn, comes in many forms.