The chapter proposes a theoretical explanation of the phenomenon of the Upper Paleolithic Revolution as a rapid, steady technological and cultural progress, a qualitative leap in the development of H. sapiens in Western Eurasia 50–30 thousand years ago. Sapienses replaced Neanderthals, partly interbreeding with them. Neanderthals, living in small dispersed groups, reached a certain equilibrium with their environment, which resulted in the cessation of further evolution and loss in competition with more numerous and developed hominins from Africa and the Levant. The author presents widely discussed reasons for the superiority of Sapiens and highlights three groups of additional factors (megafactors): (1) the combination of the special accumulated social and cognitive potential of Sapiens in Africa and the Levant with challenges-threats and challenges-opportunities in Eurasia, (2) the effect of multiple waves of settlement, cultural exchange between them, (3) the development of special social orders that promoted innovation. The potential of Sapiens gained through the “African springboard” included not only technology, but also delayed maturation and the appearance of adolescence. These characteristics led to better transmission of accumulated experience, achieved levels of verbal and cognitive development such as guided communication, supra-situational thinking, and the ability to form peaceful intergroup alliances. Faced with harsh climatic conditions, Sapiens quickly learned to fashion skins, sew clothing, make shoes, and construct dwellings. The scarcity of stone raw materials stimulated the development of new materials (bones, horns, tusks) and the invention of microliths. Sapiens adopted many Neanderthal technologies and practices, combined them with their own skills, and improved upon them. Each new wave of migrants brought different technologies, leading to the formation of “transitional assemblages”: localized cultural complexes that combined elements of different traditions. This diversity, together with practices of exchange and borrowing, created a favorable environment for selecting the most effective solutions. The “new economy” of deferred obligations and individual sharing strategies, which stimulated invention and creativity to enhance prestige, and the development of kinship systems, significantly altered social orders. Linked to the same processes was the proliferation of jewelry as a marker of status and group membership. Among the advantages of the new age structure developed in Sapiens was the emergence of grandmothers freed from childbearing, which contributed to more effective child rearing and the development of a “broad-spectrum economy”. Finally, the author formulates hypotheses to indirectly assess the validity of the argumentation.