||Students should become familiar with the basics of High Energy Astrophysics, not only with respect to the sources and astrophysical processes that produce X rays, gamma rays and cosmic rays in our universe, but also with the instruments that detect these photons / particles. The course is divided into three blocks. The first part is a theoretical description of the main processes of interaction of matter and radiation in the X- and gamma-ray energy domain. The second one describes the detectors that are currently operating, those under construction and those being designed. The third and final block presents the phenomenology of several cosmic sources of X rays, gamma rays, cosmic rays that have been observed so far.