How does the Audi Quattro all-wheel-drive system work?

I am considering buying an Audi and I've heard good things about their Quattro all-wheel-drive system. But I'm not sure how it actually functions and if it's worth the extra cost. Can someone explain it to me?

The Audi Quattro all-wheel-drive system uses a combination of sensors, computers, and mechanical components to constantly monitor road conditions and distribute power to the wheels with the most traction. This greatly improves handling and stability, especially in wet or snowy conditions.

I've had an Audi with Quattro for years and I can never go back to a car without it. My advice would be to go for it, you won't regret it.