Scattering Theory is a framework in physics that studies and describes how particles, such as electrons or photons, interact with each other and with potential barriers. It is essential for understanding various phenomena in quantum mechanics, where the behavior of particles can be quite different from classical expectations. In Scattering Theory, the focus is on how incoming particles are deflected or absorbed by a target, leading to observable outcomes. This theory has applications in fields like nuclear physics, particle physics, and even astrophysics, helping scientists predict the results of experiments and understand fundamental interactions in nature.