While claiming the allegiance of more than 70 percent of the country's population, Russian Orthodoxy is by no means the only religion in Russia. Even after the break-up of the Soviet Union, substantial numbers of Muslims, Roman Catholics, Protestants, and Buddhists remain within Russia's boundaries. The largescale emigration of Jews during the past two decades has reduced Judaism's ranks to fewer than one million.
The most comprehensive book in English on religions in Russia is The Modern Encyclopedia of Religions in Russia and the Soviet Union.
You can find links to online resources on Orthodox Christianity and other religions at a McKinley Internet Yellow Pages 4-star Web site, Facets of Religion. For still more links, try the McKinley Magellan Internet Guide.