Tensor analysis is essential to modern physics because it allows physicists to describe the physical properties of materials in a very concise way. For example, consider a metal wire. A metal wire has certain electrical properties, and these properties can be described using tensors. A physicist can use tensors to calculate the current flowing through the wire, the voltage between the ends of the wire, and how much energy is stored in the wire. Tensor analysis is also used in general relativity and quantum mechanics. In fact, tensors play a central...