The article commemorates Dmitry Dmitrievich Kasyanov (1 November 1956 – 10 July 2026), a translator, psychologist, publisher, and one of the pioneers in the development of transactional analysis in Russia. It describes his work with the first training groups, international trainers, professional texts, and organizations. The article draws on published interviews, colleagues’ recollections, and accounts of the earliest seminars, the establishment of SITA, and the activities of the Metanoia publishing house. Particular attention is paid to Kasyanov’s translation of “TA Today”, performed at a time when professional literature circulated in typewritten copies. The article analyzes his contribution to the development of Russian-language terminology and the creation of shared professional language for the training and practice of Russian professionals. The article focuses on the ways in which the new theory entered the Russian professional community: interpreting during seminars, typewritten texts, discussing terminology, and engaging in collaborative organizational work. Colleagues’ recollections illuminate his work as an organizer, interpreter, publisher, and member of the professional community. The article traces how the meetings, books, translations, and organizational initiatives of Dmitry Kasyanov created conditions for the development of transactional analysis in Russia and became part of the collective memory of Russian practitioners.