The monograph is based on the Master thesis in General History and contains a study of the cult of the Ancient Egyptian god Thoth, whom the Egyptians identified with the Moon, time, writing, calculations, medicine, magic, and intellectual activity, in general. T. started his thesis during his internship at the University of Berlin. The topic – a description of the cult of a deity – was traditional for the German Egyptological school (suffice it to say that T.'s teacher O.E. Lemm, who defended his own thesis in Leipzig, studied the cult of Amun). However, T.'s thesis was completely unconventional for its time. It was not a simple collection of facts, but demonstrated the author's high qualifications in the field of General History and Source Studies. He criticized attempts of predecessors to present Egyptian culture as devoid of dynamics and to examine early religious views through the later testimonies of Classic authors. In his research, T. was guided with the desire “to trace, on the basis of the available material, the historical development of the ideas of ancient Egyptians about the deity in which they personified their culture, with whose name they combined the idea of the ideal of truth and wisdom and which, albeit in a foreign shell, survived his civilization for a wider role, continuing to remind of it for a long time in the literatures of younger peoples”. When studying the phenomenon of religion, T. pays much attention to the landscape and climate of Egypt, the observation of ancient Egyptians, and the game of homophones in the Egyptian language. In particular, he notes that the zoolatric component of the cult of Thoth is largely associated with observations of the appearance and behavior of ibis and baboon. Ibis feeds on snakes and scorpions, and, therefore, could be seen as purifier and doctor. Baboons waving their paws strongly at the sunrise, so, they were connected with the cult of the Sun deity. The Egyptian word for ibis habu is consonant with the verb hab ‘to send’; hence, the association with Thoth as ‘the ibis sending kings’. T. resolutely refutes the euhemeric idea of Thoth-Hermes as a deified cultural figure. He arranges all the written and pictorial material in their chronology, going from the name of the deity to the place of his worship, then to local and general Egyptian mythology, images and cult, and, at the conclusion, he briefly examines the mythology of Thoth in the Phoenician, Ancient Greek, and Coptic literatures. The author gradually clarifies the long process of transformation of the god-healer into the deity of the royal and afterlife court, the patron of school and knowledge, ‘Lord of Time’, and ‘Prince of Truth’. The Appendix contains all the epithets of Thoth known to the author from the Old Egyptian to the Greco-Roman times, images of Thoth and unpublished texts from private collections. All the monographs of Russian researchers (I.G. Frank-Kamenetsky, I.M. Volkov) on the cults of deities of the ancient world were subsequently based on this methodology. The thesis was also known abroad, but was not widely cited, since it has not been translated into European languages.