Alexei Alekseevich Ukhtomsky (1875–1942), a world-famous physiologist, had encyclopedic knowledge in the fields 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 properly accepted today. This collection, including the diary entries of A. A. Ukhtomsky and his correspondence, is intended to draw the attention of the thoughtful reader to this original intellectual prose.