APPLYING THE METAPHOR of seasons to the different stages in a man's life has long been a common practice for writers of the most varied sort--psychologists, novelists and playwrights through the ages have all taken up the phrase. But no one has ever gone beyond the literary use of the term to explore just what the concept of seasons in a man's life really means. Although psychologists Erik Erikson and Jean Piaget have discovered, through intensive study and observation of children, that people go through a given sequence of developmental phases in the early years of life, no full-scale or systematic study of the entire life course has ever been attempted--until Daniel Levinson and his co-workers at Yale in 1968 began the research that has finally resulted in his long-awaited book, The Seasons of a Man's Life.

Many of the juiciest conclusions of the book have been, as it were, leaked to the world by Gail Sheehy, author of the best-selling Passages, which set forth the basic thesis enunciated at greater length and in more detail here: that all people go through an age-linked series of developmental stages in adult life, each with its specific psychological and social tasks and each the necessary base on which to begin the next phase of adult development.

Levinson has consciously tried to avoid the pitfalls of so many other studies of men in their worlds: a too-narrow focus of research. Psychologists tend to study the ego's changing role and function (Erikson) or a man's changing defense mechanisms to deal with the world (Harvard's George E. Vaillant); sociologists focus on men's work or class or world-view; anthropologists on the nature of his ties to his family, community, religion, or nation. Levinson, however, is anxious to put his new discipline on a more secure, if ambitious, footing; he wants to study what he calls "the fabric of one's life," a man's complete "life structure" which embodies his occupation, relations to parents, friends, lovers, children, his varied social roles and self-definitions, and his basic choices, problems and paths in life. Through this over-arching concept

We may examine the interrelations of self and world--to see how the self is in the world and the world is in the self. When an external event has a decisive impact, we consider how processes in the self may have helped to bring it about and to mediate its effects. When an internal conflict leads to dramatic action, we consider how external influences may have touched off the conflict and decided how it would be played out.

According to Levinson the stages of the life cycle, and the transition periods which link the major eras, fall in the following definite pattern (allowing for a few years spread in each case to account for individual variation):

0-17--Pre-adulthood. A person builds a basic sense of identity, tries on different self-conceptions and roles, makes first hesitant steps towards joining the adult world.

17-22--Early Adult transition. First significant life choices, major steps towards reducing dependency and becoming self-reliant.

23-40--Early adulthood. This is the summer of life when a man is at the peak of his biological and mental capacities, choosing an occupation and moving up the ladder of his career, forming a stable life structure, raising the next generation, establishing his place in society.

40-45--The much-heralded mid-life transition, or midlife crisis as more sensationalist authors would have it. What does it all mean?, why have I been working on this task all this time?, am I content with the choices I have made?, can I read Camus?, often plague a man in this time of reappraisal and redirection.

45-60--Middle adulthood. Integration of some of the aspects of the self that have earlier been neglected--the more "feminine" side, the nurturing, emotional and loving side. Often a man acts as a mentor to the next generation in his field--furthering their progress, feeding their dreams, much as he himself grew under the influence of a mentor in his early adulthood. A more balanced life ensues--with the acceptance of mortality, the realization that he will not be the hero of his dreams, the decision to invest more time and energy in the non-work aspects of life.

60-Death--Late adult transition. Time to give up authority, the center stage, to accept limitations. Having paid his dues to society, a man can pretty much do whatever he damn well pleases as long as circumstances of health and security allow. Much less is known about this period than the earlier ones.

Crucial to his theory of adult development, as Levinson emphasized in his speech at Harvard last week, is the concept of the Dream, and the related concept of the Mentor. In forming a concept of himself, a young man necessarily imagines an ideal life for himself, whether he focuses on his career, relationships, or his intellectual life is unimportant; so long as he creates a mental picture of the Dream he will pursue his development is on course. He will modify the Dream as he grows and changes and learns about his life and himself, and he may even change one dream for another, but the mental picture in his head acts as a sort of psychological carrot. A mentor, an older man who helps the growing adult fit into his society and who aids his development in many ways, may become critical in the phase of Early Adulthood. Besides the obvious functions he serves--integrating the adult into his career, teaching him, giving him a role model, smoothing the way for him, fostering his intellectual and moral development--the Mentor believes in the Dream, and in the dreamer, and makes the adult believe in himself. In a sense, he cleans off the mental carrot so it will be ready for consumption.

ONE'S FIRST reaction to all this is: so what? Does anyone really care what one is supposed to do at forty or what the developmental tasks and integrations of the period are? As Levinson points out, knowing more about what happens to men at what age makes it easier to sort out one's own life, realize one is not alone, and makes it easier for society to appropriately deal with its citizens of all ages and utilize their unique resources.

Levinson's study is not the only one to reach the conclusion that a discreet life cycle exists. The recently-published Grant study of the lives of men who went to Harvard, as well as other work in the rapidly-expanding field of life history, support Levinson's idea of the life cycle. And, as so often happens, the common sense wisdom of the ages does too, although no one fully realized it until a systematic, scientific study like Levinson's pointed it out. The Greek scholars, Confucius, the Bible, Shakespeare all speak explicitly of the seasons of a man's life, although they are not as precise as to the dates of onset of periods and crises.

No small task that Levinson has set for himself. One would therefore expect such a momentous and arduous study to be supported by dozens of researchers using impeccable research methods with hundreds of thousands of dollars in grants from big foundations. Instead, Levinson's group consists of about five interviewer/researchers who selected a sample of forty men to interview in depth about their life and work and values and crises. In essence, Levinson chose to write the biographies of 40 men and see if any underlying similarities appeared. This is hardly the kind of base one would feel comfortable with in building a new academic discipine.