IF I HAD my life to live over, I would dare to make more mistakes next time. I would relax. I would be sillier, I would take fewer things seriously . . . I would eat more ice cream and less beans . . . If I had to do it again, I'd travel lighter." So says an 85-year-old woman in Rabbi Harold Kushner's When All You've Ever Wanted Isn't Enough, the follow-up to his best seller, When Bad Things Happen to Good People.

Kushner's present volume isn't about dealing with the awful things that happen to us, however. This time he's concerned with how we handle the so-called good life. People kill themselves amassing money, power, social status and physical comfort, yet feel strangely unsatisfied in the midst of their riches. They are bored, depressed, only half alive and afraid to die. Material "rewards create almost as many problems as they solve," says Kushner. "Sooner or later we will come face to face with the questions, What am I supposed to do with my life? How shall I live so that my life will mean something more than a brief flash of biological existence soon to disappear forever?"

These are ancient questions, of course, addressed through the ages by a holy army of saints, philosophers, theologians and these days by TV evangelists and the upbeat authors of self-help books. Their answers range from renunciation of the material world and self-sacrifice in the service of others to looking out for number one and outright hedonism. None of these is the answer, says Kushner.

"Trying to find one Big Answer to the problem of living is like trying to eat one Big Meal so that you will never have to worry about being hungry again. There is no Answer, but there are answers." And these, says the rabbi, are to be found in daily life, in filling "each day with one day's worth of meaning," with the love of friends and family, with striving to acquire integrity instead of gold. Kushner builds much of his argument around Ecclesiastes, "the most dangerous book in the Bible" (because it asks us to think about life instead of blindly worshipping), an account written by an angry, cynical man who "cannot handle that fear of dying and leaving no trace behind." We must learn, like Ecclesiastes, says Kushner, that life is its own reward, that death is less fearful than never having lived, and that "the worst hell is the realization that you could have been a real human being . . . a mensch . . . generous and truthful and loyal . . . controlling your instincts instead of letting them control you, and you never did it."

Summarized so, this may sound trite, a collection of pious short-cuts. But Kushner's book is, like Scott Peck's The Road Less Traveled, a thoughtful, well-reasoned meditation and a useful spiritual survival manual.

Judith Viorst's desire to know more about the human psyche led her to become a student at the Washington Psychoanalytic Institute. She became, after six years of study, a research graduate in 1981, underwent analysis, and worked as a therapist -- an unusual departure for someone who was already a well known poet, Redbook columnist, and author of a dozen books for children and adults. Viorst chose a psychoanalytic institute because "at its best, psychoanalytic theory offers us illuminating generalizations while maintaining an exquisite respect for the complexity and uniqueness of each of us astonishing human beings."

VIORST thus brings an unusual perspective to Necessary Losses, a book that explores the painful separations we must continually undergo. She begins, quite naturally, with our first profound loss, that of leaving the womb, and traces our path via a chronology of angst: leaving and losing our mothers; losing our specialness as children; abandoning our dreams of power and mastery; saying goodbye to our children; losing friends and loved ones to death; and finally, facing the ultimate loss of ourselves.

Yet while Necessary Losses glides above a landscape of heartache, it's never clinical or depressing. Viorst is, after all, a poet with a wonderful sense of humor and insight. She skillfully combines psychoanalytic theory, poetry (her own and others), interviews (Liv Ullman and Benjamin Spock appear), anecdotes, and her personal experiences into an instructive yet warm survey of the human journey.

Her heavy reliance on Freudian theory, for example (Freud is cited 40 times, Jung never -- not even in the chapter on dreams), is balanced by her generosity in using her intimate experiences as examples of how we experience and survive losses. She writes of her sister's death: "Lois -- the great rival of my childhood, the tagalong pest I had come so deeply to love -- has died of cancer in the autumn of this awful year, just as I sit down to write this chapter . . . There are people like Lois at every age and with all kinds of fatal ailments who hang on to hope, who fight to stay alive, trusting in will, in spirit, in remissions, in brand-new miracle drugs or -- in miracles. 'Don't they know they can't make it?' we may wonder, having heard the grim statistics. But they have heard them too, and what they do is tell us, and themselves, 'I'm not a statistic.' "

That, of course, is the sum of Viorst's richly detailed work, that we are, each of us, unique and separate, yet bonded into a human family by necessary losses. And though she has taken a different route from Rabbi Kushner, and speaks from a different perspective, Viorst comes to similar conclusions about the importance of love and growth. As a 68-year-old woman friend of hers says, "reality is full of wonder."