This study spans the entire life and work of the Russian philosopher Lev Shestov (1866-1938). It offers keys to understanding his thought, while also tracing the historical itinerary of his work. Shestov’s thought is not only interesting in itself, as a “philosophy fighting against philosophy,” but also because it reveals an entire world of cultural connections in its extraordinarily keen exploration of other “souls.” The reader will find in Shestov some of the sharpest analyses of authors such as Shakespeare, Nietzsche, Tolstoi, Dostoevskii, Luther, Plotinus, Pascal, Kierkegaard and many others. This study will better determine the controversial and fascinating philosopher’s place in the history of Russian and Western thought.