Electromagnetic wave propagation in a randomly inhomogeneous medium as a problem in mathematical statistical physics

The major stages of how mathematical statistical physics has been used in the last fifty years to describe random medium electromagnetic wave (light) propagation are outlined. The statistical description is discussed either in terms of the scalar parabolic equation (quasioptical approximation) — when the governing parameters are needed, or by writing its functional integral solution — if the caustic structure of the wave field is to be analyzed.