What is adaptive cruise control and how does it work?

I'm considering purchasing an Audi A5 and noticed it comes with adaptive cruise control. Can someone explain what this feature does and how it operates?

Adaptive cruise control is a driver-assistance feature that helps maintain a safe following distance between your car and the vehicle in front of you. It uses sensors and cameras to detect the distance and speed of other cars on the road. When activated, the system will automatically slow down or speed up your car to maintain a safe distance.