Sergey Sergeievich Korsakov (1854-1900) was an outstanding Russian psychiatrist, founder of the Moscow psychiatric school, a talented clinician and teacher, and a supporter of the nosological approach in the understanding and systematization of psychiatric illnesses. He described alcoholic polyneuritis with distinctive mental symptoms, which later on was coined "Korsakov's disease." He was the first to give a clear account of paranoia. Korsakov was a leader in more humane patient management by applying no-restraint principles.