valentin fyodorovich bulgakov (; 25 november 1886 in kuznetsk, russian empire – 22 september 1966 in yasnaya polyana, tula oblast, soviet union) was the last secretary of leo tolstoy and his biographer. he was director of a number of literary museums and was engaged in tolstoyan, pacifist, and anti-communist activities. he was imprisoned by both the tsarist and soviet regimes and was a nazi concentration camp survivor. during the final 20 years of his life he was head of the yasnaya polyana museum.