It was this topic, above all others, that attracted my attention to the statistics of natural phenomena in the first half of 1990. By that time, the energies of the rays were already measured in more than ten orders of magnitude and their spectrum was the number of particles measured per unit area per unit time, and even coming from a unit solid angle of space. Such a spectrum has a power-law form and is shown in Fig. 4.1. These are mainly galactic cosmic rays. Cosmic rays with energy less than \(1\,{\text{GeV}} = 10^{9} {\text{eV}}\) are created mainly in the solar corona. High energy rays have galactic and extragalactic origin. The main source of energy for them is supernova explosions. The most complete description of the processes associated with cosmic rays can be found in the book “Astrophysics of Cosmic Rays,” published in 1990 in Russian and English edited by Ginzburg (Astrophysics of cosmic rays, North Holland Publications Co., Amsterdam, 1990), which has remained virtually unchanged since then.