Prince Evgenii Trubetskoi (1863-1920), one of Russia's great philosophers, exemplified what was best in the Russian religious-philosophical tradition. His lifelong pursuit was "e;integral knowledge."e; This ideal affirmed that faith was integral to reason and that inner experience (moral, religious, aesthetic), and not just external sensory experience, offered truthful testimony to the nature of reality--precisely contrary to the reductive positivism and scientism of Trubetskoi's day and ours. Following Vladimir Soloviev he developed the concept of Bogochelovechestvo (divine humanity)--the free human realization of the divine principle in ourselves and in the world (deification)--and found in it the very meaning of life. Trubetskoi strikingly combined religious philosophy with an unwavering commitment to the main principles of liberalism: human dignity, freedom of conscience, the rule of law (based ultimately on natural law), and human perfectibility (progress). He worked tirelessly for a liberal, constitutional Russia. This is the first book in English devoted to Evgenii Trubetskoi's life and thought. It includes a comprehensive introduction, six chapters on his religious-philosophical worldview, and six chapters on an area of religious studies that he inspired--the philosophy of the icon.