Itô Calculus is a branch of mathematics that deals with stochastic processes, which are systems that evolve over time with inherent randomness. It was developed by Kiyoshi Itô in the 1940s and is essential for modeling phenomena in finance, physics, and other fields where uncertainty plays a significant role. The core concept of Itô Calculus is the Itô integral, which allows for the integration of functions with respect to stochastic processes, particularly Brownian motion. This framework provides tools for analyzing and solving stochastic differential equations, making it crucial for understanding complex systems influenced by random fluctuations.