Children have stages, said Erik Erikson; adults have stages, said Daniel Levinson and Gail Sheehy; and now, says this team, couples have stages as well. So what else is new? asks anyone who has ever been in a sustained relationship. What's new is that Dym (Clinical Psychology/Harvard Medical School) and Glenn (a psychiatrist) have attempted to codify the stages. First comes ``Expansion and Promise'' (the honeymoon), then ``Contraction and Betrayal'' (the end of the honeymoon), and, finally, ``Resolution'' (compromise). In Expansion, the lovers flower, each presenting the best that they can be, each seeing the other through an amber lens. In Contraction, reality sets in as the lovers fall back on old patterns and view each other as if in a police lineup. Uninhibited charm becomes empty-headed chatter; quiet strength becomes stubborn withdrawal. In Resolution, the lovers negotiate, and appreciate their differences. Unlike other stage theories, the authors' doesn't plateau at a final stage; instead, the cycle replays again and again until the relationship ends or the periods of happy Expansion or acceptable Resolution override those of painful Contraction. Unfortunately, however, misery seems to dominate the case histories, which also seem to highlight stereotypes--for example, whiny women and disaffected men, a selection that seems retrogressive after a generation of women have struggled for independence, and men for sensitivity. Despite some nuggets--among them a discussion of the character of the couple as distinct from the characters of its participants- -the discouraging examples and types undermine the authors' messages.