Bus Mastering is a method used in computer systems where a device, known as a bus master, takes control of the data bus to communicate directly with other devices. This allows the bus master to send and receive data without needing to go through the central processing unit (CPU), improving efficiency and speed in data transfer. In a typical setup, multiple devices can share the same bus, but only one can be the bus master at a time. This process helps manage data flow and ensures that devices like graphics cards or network interfaces can operate effectively without interference from others.