The article presents the review of contemporary literature on the problem of the Flynn effect (FE). The FE is the increase of intelligence tests scores throughout the XX century with the rate of approximately 3 IQ points per decade. The article describes the essence of the FE and methods of its measurement, metaanalytical data on the size and stability of the FE between populations and in time.  Authors also considered the manifestation of the FE in cognitive tasks different from intelligence tests, and in the domain of intellectual achievements. The special attention is devoted to the discussion of the causes of the FE. The most popular hypotheses are the environmental explanations of the FE (improvement of nutrition, changes in the family structure, growth in quantity and quality of cognitive stimulation, etc.). Along with that, there are explanations which connect the FE with genetic changes, as well as with artifacts that appear in the process of intelligence testing. It is also debated whether the FE depicts the real increase in intelligence in people. The data is provided that shows that the FE is more pronounced in tasks that have lowest loadings on the general factor of intelligence (g factor). At the same time there is data that prove the decrease in genotypic intelligence. It is concluded that the FE is associated with the change in structure of cognitive abilities and acquisition of problem solving skills, which capture rules and abstract reasoning operations. Thus the FE masks the tendency of decrease in genotypic intelligence. In the conclusion of the article the practical consequences of the FE in the sphere of education, forensic practice and social policies are analyzed.