 The Feynman propagator is a solution of the quantum Hamilton Jacobi equation, which can be calculated using either the path integral method or the Hamilton Jacobi equation. In the former, the path integral is used to compute the propagator, while in the latter, the propagator is derived from the classical Hamilton Jacobi equation. Both methods yield the same result, but they differ in their approach. This article was authored by Mario Fosco Girard.