The lectures demonstrate that the density matrix is a compact method of specifying the polarization. In this regard, we consider here the density formalism of the beam and show that the density matrix of the beam is a very convenient tool for describing the scattering and polarization of protons by nuclei. Based on the presented formalism, we obtain expressions practically for all the observed quantities that we managed to extract in the experiment. In this part of the Lecture Course we briefly describe the methodology for obtaining the triple scattering parameters introduced by Wolfenstein for the description of nucleon-nucleon and nucleon-nucleus scattering. In this description we are based primarily on the formalism developed, summarized and modeled by Ohlsen after that of Wolfensterin.