A Turing Machine is a theoretical computing model introduced by mathematician Alan Turing in 1936. It consists of an infinite tape divided into cells, a tape head that reads and writes symbols, and a set of rules that dictate its operations. This model helps in understanding the limits of what can be computed. Turing Machines are fundamental in the field of computer science as they provide a simple yet powerful framework for defining algorithms and computation. They are used to explore concepts like decidability and complexity, forming the basis for modern computing theories and practices.