Published online by Cambridge University Press: 19 July 2016
About one half of all stars are close binaries whose components can efficiently interact during their evolution. The interaction of the components significantly influences the evolution and changes the chemical composition of their atmospheres. This review is devoted to the discussion of the binarity role in the creation of stars with an anomalous chemical composition of their envelopes: WR, OBN, OBC, RCrB, Ba, sdBO, Am, Fm, Ap, Bp, helium stars, CO stars, Na giants.