What is nose-to-tail dining and how did it come about?

What exactly is nose-to-tail? Literally, just that. No part of the animal is wasted. Well, except the hooves, nails and beak. But every inch of flesh is consumed, be it the cheek, tongue, rump, kidney, brain, liver, even testicles. It's a philosophy that also extends beyond meat to vegetables and plants, by the way.