Information Theory is a branch of applied mathematics and electrical engineering that deals with the quantification, storage, and communication of information. It was founded by Claude Shannon in the 1940s and provides a framework for understanding how information can be measured and transmitted efficiently. The theory introduces key concepts such as entropy, which measures the uncertainty in a set of outcomes, and channel capacity, which defines the maximum rate at which information can be reliably transmitted over a communication channel. These principles have profound implications in fields like telecommunications, data science, and cryptography.