Exposure to indirect ionization should be considered one of the most important ways of radiolytic decomposition of a substance mixed with other substances and exposed with them to ionizing radiation. In a complex set of indirect ionization processes, the primary act is the transfer of an electron from molecules of one substance to ions of another. These processes can be investigated so far only on the simplest mixtures of organic substances. But studying these processes opens the way to understanding the whole complex picture of the effects of ionizing radiation on living organisms both in space and on Earth.