TRUBETSKOI, SERGEI (1862–1905), scion of an old noble family in Russia, was professor of philosophy at the University of Moscow. Weeks before his death Sergei Nikolaevich Trubetskoi became the university's first elected rector. He was instrumental in popularizing philosophical idealism. His philosophical and religious convictions led him to take public stands on the major issues of the day, positions which brought him national prominence. At an audience with the tsar in June 1905 Prince Trubetskoi was the spokesman of the moderate liberals. A close confidant of Vladimir Solov'ev, Trubetskoi worked within the philosophical tradition of idealism that encompassed Plato, Kant, the Russian Slavophiles, especially Ivan Kireevskii, and the Western mystics, particularly Jakob Boehme. Trubetskoi's interest in the history of philosophy led him to the history of religion. He wrote an introduction to the Russian edition of Karl Barth's Religions of India and prepared a bibliography on the history...