 Korotayev has thereby discovered the phenomenon of consolidation of the clan organisation in North-East Yemen in the late 1st millennium BCE as well as the transition from chiefdoms to tribes in early medieval Yemen.He was also the first to provide convincing evidence for the existence of matrilineal descent organisation in Pre-Islamic Arabia and to suggest an adequate translation of the largest Qatabanic inscription, R 3566.Korotayev and his colleagues have also made significant contributions to the study of political-demographic dynamics in Subsaharan Africa, especially, the problems of the Tropical African countries' escape from the Malthusian trap.