Аннотация:The factors determining the selectivity of radiation induced processes in solid hydrocarbons of various classes and related polymers are reviewed. Special attention is paid to the recent experimental results. The following aspects of the problem of selectivity are considered: 1) localization of primary radiation-induced effects at the level of specific links and chemical bonds; 2) effect of molecular dynamics on the selectivity of the reactions of active species in irradiated polymers; 3) specific features of radiation induced processes in microheterogeneous bicomponent polymer systems (with the example of styrene-butadiene block-copolymers). It is concluded that the selectivity of primary bond scission in hydrocarbons and polymers correlates with the structure of the corresponding ionized molecules (radical cations) and appears to be determined by conformations and molecular interactions. Local radical reactions in irradiated polymers, which occur under the conditions of inhomogeneous spatial distribution of active species at low temperatures, are found to be rather specific from the viewpoint of mechanism and reaction products. These processes are very sensitive to small-scale molecular motion. In microheterogeneous polymer systems, in addition to the processes occuring independently in separate microphases, one has to take into account the possibilities of charge and excitation transfer in the interface region and of the interphase migration of active species.