A dog doesn't care if you are rich or poor, educated of illiterate, clever or dull. Give him your heart and he will give you his. It was really quite simple, and yet we humans, so much wiser and more sophisticated, have always had trouble figuring out what really counts and what does not.

He taught us the art of unqualified love. How to give it, how to accept it. Where there is that, most other pieces fall into place.

In a dog's life, some plaster would fall, some cushions would open, some rugs would shred. Like any relationship, this one had its costs. They were costs we came to accept and balance against the joy and amusement and protection and companionship he gave us.

There's no such thing as a bad dog, just a bad owner.

A person can learn a lot from a dog, even a loopy one like ours. Marley taught me about living each day with unbridled exuberance and joy, about seizing the moment and following your heart. He taught me to appreciate the simple things-a walk in the woods, a fresh snowfall, a nap in a shaft of winter sunlight. And as he grew old and achy, he taught me about optimism in the face of adversity. Mostly, he taught me about friendship and selflessness and, above all else, unwavering loyalty.

When I wrote 'Marley & Me,' I had a clear audience in mind. And it did not include children. I wrote my book for adults and assumed only adults, and possibly teenagers, would be drawn to it.

Only then did I see. Something was amiss with Patrick's snap-on one piece, or "onesie" as we manly dads like to call it. His chubby thighs, I now realized, were squeezed into the armholes, which were so tight they must have been cutting off his circulation. The collared neck hung between his legs like an udder. Up top, Patrick's head stuck out through the unsnapped crotch, and his arms were lost somewhere in the billowing pant legs. It was quite a look.