Whether you call it Open or Open-Ended it means marriage which doesn't rest on traditional monogamy and fidelity and leaves room for the ""creative and moral uses of extramarital sex."" Mazur's training as a Unitarian Universalist minister comes through in this soft-spoken reappraisal of the ""covenant"" which need not be exclusive. The taboo against sex outside of marriage says Mazur is, when carried to extremes, ""a cultural neurosis"" which can stifle human growth and self-realization. A new social climate which fosters pluralism in sexual standards is on the horizon; ""adultery is a theological judgment, . ."" one which Mazur dislikes as he dislikes all the restrictive codes and double standards which spread fear, shame, irrational guilt and possessiveness -- ""a dehumanizing process."" It's a point of view that's being heard a lot these days and Mazur's exposition of OEM is thoughtful and modulated with none of those flamboyant, wild-eyed calls for swinging and swapping and letting it all hang out which so often characterize books proselytizing for new lifestyles.