The question of the origin of elements from the very beginning of their appearance and throughout the entire history of its development has always been closely and inextricably linked with the question of the transformation of elements. This book shows that the synthesis of chemical elements can occur at all stages of stellar development in close connection with nuclear reactions, which ensure the luminosity of stars, their chemical composition and evolution. It is also said that the synthesis of element nuclei and their destruction in outer space, nebulae and bodies such as the Earth and meteorites are natural processes in the evolution of matter in the Universe.