The middle years are said to be the prime of life, a time of anticipated stability and serenity. Middle-aged people describe themselves as "the powerful age group vis-à-vis other age groups"; they say that "they are the norm-bearers and the decision-makers; and they live in a society which, while it may be oriented toward youth, is controlled by the middle-aged" (Neugarten 1968, p. 93). Yet there is trouble in paradise. A large number of couples appear in the therapist's office at midlife, some from long-troubled marriages, but others from marriages that by many standards seemed highly successful. Ironically, they come in large numbers at a time when they seem to be under less strain in many areas of their lives. They may be more financially secure, more established professionally and socially, less controlled by the demands of young children. This reveals something of the internal paradox of marriage, a relationship marked by continual change in the partners and thus continually becoming different from the relationship to which a lifelong commitment was made. Change is most obvious when marked by external shifts in roles due to things such as the birth of a child or a career change. But change is the reality; people do not simply live happily ever after. I will argue that midlife is a key time of change and that the heightened reflection characterizing that period offers unusual opportunities for personal and interpersonal growth at the same time that it confronts people with the changes time has wrought.