A Green's Function is a mathematical tool used to solve differential equations, particularly in physics and engineering. It represents the response of a system to a point source or impulse, allowing for the analysis of complex systems by breaking them down into simpler components. In many applications, such as electromagnetism and quantum mechanics, Green's Functions help find solutions to boundary value problems. By using these functions, one can determine how a system behaves under various conditions, making them essential for understanding wave propagation, heat conduction, and other physical phenomena.