This is a textbook for graduate students entering the field but at the same time a cosmic ray manual for high energy astrophysicists. The first part, easy to read for the general astronomer, describes the standard model of cosmic rays based on our understanding of modern particle physics. The acceleration scenario is presented in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Experimental data in the atmosphere as well as underground are compar ...