Infinitesimal Calculus is a branch of mathematics that deals with the study of change and motion. It focuses on concepts such as limits, derivatives, and integrals, which help in understanding how quantities vary and accumulate. This field is essential for analyzing functions and solving problems in physics, engineering, and economics. The development of Infinitesimal Calculus is attributed to mathematicians like Isaac Newton and Gottfried Wilhelm Leibniz in the late 17th century. Their work laid the foundation for modern calculus, enabling advancements in various scientific disciplines. Today, it remains a crucial tool for modeling real-world phenomena.