Many scholars and critics have maintained that Tolstoy, while a great writer, is a poor thinker, a mere amateur in philosophy. My chapter suggests that this venerable cliché of Tolstoy reception is untenable. The chapter has two parts. In the first, I discuss several philosophers with whose thinking Tolstoy engaged extensively and give a brief account of his relation to them. The main names here are well known: Jean-Jacques Rousseau, Arthur Schopenhauer, and Immanuel Kant. In the second part, I examine a somewhat unexpected but significant affinity Tolstoy’s fiction has with the thought of Baruch Spinoza. This affinity emerges most clearly in War and Peace. Although this section covers what is merely an affinity, it aims to show that Tolstoy’s greatest fictional work is one of the supreme artistic instantiations of an essentially Spinozist account of the world.