It is the largest work by Z., started in the late 1920s, was published only in the mid-1960s, many years after the tragic death of the author. The book has received worldwide recognition. It contains extensive information on the tribal formations of various primordial peoples: their organization, mythology, cosmogony. The book analyzes dualistic myths and dual-clan organizations of archaic societies in Australia, Melanesia, Polynesia, South and North America, Africa, India, Indonesia, Siberia, and Eastern Europe.

The main task of the book is to substantiate, relying on the broadest ethnographic, historical, and folkloristic material, the idea that the dual organization was “the most ancient form of the structured society”, which developed directly from the ‘primitive herd’, which curbed the “animal in man” and determined the whole structure of life of primordial man: the economic organization, the organization of tribal power, marriage norms, human behavior, the procedure for performing religious rites and ceremonies. According to the researcher, the dual organization structured the worldview of primordial man and determined its development from the simplest myths about twin-siblings to complicated concepts of the paired supreme deities of the ancient dualistic religions. Z. writes in the ‘Conclusion’: “One can say, that in the dual organization and twin myth we have found a wonderful root of life, from which a variety of ramifications of social, religious, mythological, epic, and fabulous creativity of mankind have grown, a root that helps to understand fossilized institutions, resurrect ancient forgotten heroes, revive their faded features, restore their ancient exploits and bring them out of the dark depths of popular memory into the bright field of scientific knowledge".