Fyodor Dostoevsky (1821 – 1881) was considered one of the greatest Russian writers, whose works have had a profound and lasting effect on twentieth-century fiction. His works often feature characters living in poor conditions with disparate and extreme states of mind, and exhibit both an uncanny grasp of human psychology as well as penetrating analyses of the political, social and spiritual states of Russia of his time. Many of his best-known works are prophetic precursors to modern-day thoughts. He is sometimes considered to be a founder of existentialism, most frequently for Notes from Underground, which has been described by Walter Kaufmann as "the best overture for existentialism ever written."