The monograph, prepared on the basis of numerous ethnosociological studies conducted in 1993-2002 under the guidance of the author in different regions of Russia and neighboring countries, examined the relationship between social transformations and the processes of formation of ethnic, confessional, tender, regional, political, professional, property and a number of other identities. Instead of multiple identity theory, a new concept of multiple identities is proposed, based on an understanding of multiculturalism, manifested at the personal and group levels.