Alexei Alekseevich Ukhtomsky (1875–1942), a world-famous physiologist, had encyclopedic knowledge in the field of philosophy, theology, literature and left his mark on the “hidden thinking” of Russia in the 1920s-1930s. A prince by birth, a deeply religious man, he enjoyed considerable authority among the Old Believers in the United Faith Church. The cardinal moral ideas of A. A. Ukhtomsky, not in demand in the 20th century, are not adequately accepted today. The diary entries of A. A. Ukhtomsky, included in this collection, are published according to the publications: Ukhtomsky A. Intuition of Conscience: Letters. Notebooks. Notes in the margins (St. Petersburg, 1996); Ukhtomsky A. Honored interlocutor: Ethics. Religion. Science (Rybinsk, 1997); When preparing the text by A. A. Ukhtomsky, some features of his spelling and punctuation were preserved.