Theoretical and practical works of Polish director Jerzy Grotowski, created in the second half of the 20th century, continue to produce a great impact on modern theatre worldwide. Grotowski’s experiments formed the basis for a popular trend — anthropological theatre. For the first time ever, the article considers the five periods of Grotowski’s creative legacy from the perspective of the uprise and development of a complex methodology of exploration of human nature in the framework of theatrical and ritual traditions. Drawing on the theoretical underpinning of cultural (social) and structural anthropology, on works by Jung, Eliade, Levi-Strauss, Kosinski, the author of the article addresses complicated connections of Grotowski’s practical works and terms, that he introduces at different stages, follows the use of the Polish reformist’s ideas in modern anthropological theatre. The terms, suggested by Grotowski in the context of development of anthropological theatre, are becoming an important tool for modern art criticism.