What is Audi's signature Quattro system and how does it work?

I've heard of Audi's Quattro system but I'm not sure what it does or how it works. Can you provide a detailed explanation?

Audi's Quattro system is a permanent all-wheel drive system that distributes power between the front and rear axles. It uses a center differential to continuously adjust power distribution based on road conditions, providing optimal grip and stability. It works especially well in inclement weather and on rough terrain.

The Quattro system utilizes a sophisticated electronic control unit that constantly monitors and adjusts torque distribution to each individual wheel. This not only improves traction and handling, but also enhances overall performance and efficiency.