As a new mother, I am participating in the echo of the baby boom and have had my first child at a time and under circumstances similar to that of many of my friends. We grew up career- rather than baby-oriented and since giving birth have banded together for profitable note-comparing sessions. What a relief it has been to discover that I wasn't the only one feeling so exhausted and mush-brained, and yet so in love with my daughter that I heard her voice everywhere.

As we have borne our children, sooner or later my friends and I have wondered why, with so many fine books about pregnancy, childbirth and child development available, there are so few that discuss the emotional changes that occur as we became parents.

Well, baby-boomers, now there are two such volumes devoted to just that question. "Motherhood: Your First 12 Months" examines the stages of parental development. Author Deborah Insel discusses the changes that parenthood exerts on the parents' relation to each other and the rest of the world, and the roller-coaster ride of emotions experienced in the process. It is a comforting book, full of insights that make the reader think, "Yes, that's exactly what I have been thinking." Her theme is that you are not alone in experiencing both positive and negative feelings about your new role. And in the best modern manner, Insel suggests that by confronting these feelings, new mothers will adjust more easily.

The issues Insel discusses may depress or frighten the uninitiated. Among her revelations are that after the birth, most women still look pregnant. Exhaustion has a new, unimaginable meaning. Regardless of the best intentions of the most liberated couples, the mother is not only totally dependent, often for the first time in her adult life, but also ultimately responsible for the well-being of her baby. Even when the basic tasks of child care are finally mastered, we are confronted with another problem: What do we do with this clean, dry, rested, warm and fed creature now?

Most new parents experience a gap of expectations. Because the mother generally spends more time in child care than the father, she tends to mistrust his handling of the baby, even though his participation is devoutly to be wished. This conflict comes as a surprise to most parents, as does the relegation of the husband-wife relationship to the proverbial back seat. Insel also addresses the boredom that sets in after a few months and its concomitant guilt. Most mothers fear that acknowledging these negative feelings will result in resentment of the baby, husband and the rest of the world.

Insel is not prescriptive in her discussion, and this may discourage some readers. At times she reminded me of my obstetrician who told me, in my eighth month, that there was only one cure for my painfully strained ligaments: "Have the baby." Experience is the best teacher, of course, but it helps to partake of others' as you undergo your own.

The strength of "Motherhood" lies in its linkage of the stages of child development with parent development. The weakness, and this is meant as a back-handed compliment, is its length. The book is short, and particularly in the last three chapters, the author seems to have run out of breath. She becomes repetitive, dependent on too few sources, and the pedestrian style of writing becomes even more so. Insel has done a commendable job of realizing her very good idea, but I look forward to the first revised edition of "Motherhood."

"In a Family Way: A Husband and Wife's Diary of Pregnancy, Birth and the First Year of Parenthood," by Susan Lapinski and Michael deCourcy Hinds is a much more satisfying book.

Lapinski and Hinds are professional writers, he for The New York Times and she as (what else, oh ye new mothers?), a freelancer. Consequently, their book reads as good prose, not just good insight.

As with "Motherhood," the authors' observations are no less striking for being commonplace:

Michael: "It is science fictional: a creature from outer space has invaded my wife. Textbooks say I had something to do with creating this balloon of a belly, but that seems farfetched . . .

"In public with Susie, I feel shy and notice some other people do, too. Susie's hugeness is a boast about what we do at night. Women look at the lump with great interest; men often don't know where to look."

Michael dominates the diary, at least in number of entries, and this is not surprising. How could Susan find time to write? His insight into new fatherhood is particularly welcome, although he writes from an annoyingly parochial perspective. He is extremely egocentric. They both resent, to varying degrees, giving up their beautiful, successful life style in order to have a baby. The reader is given to wonder, should they have had a baby at all? Well, yes and no. It's not a pretty experience to read about, but to their credit it rings true.

Susan's portion of the diary is highly introverted and personal, symbolic of a major aspect of new motherhood: It is not only compelling but necessary to become obsessed with the minutiae of daily mother and child care, just as it is inevitable to become estranged emotionally and sexually from the man who made it all possible. Her brutally honest description of her exhaustion, doubts and wonderment are the crucial ingredients:

Susan: "Sometimes, lying in bed, I feel like one of Dali's surreal clocks, melting, weeping, sagging under my own heaviness . . . I wonder if I'll ever be thin and calm and rested again . . . I sense that my life is turned upside down and that nothing will ever be the same again. I'm a mother."

I recommend "In a Family Way" wholeheartedly. I also defy any recent or aging parent to read this diary without getting misty-eyed at least once. If you're brave enough to want to know what they can't begin to tell you in childbirth class, here are some answers.

Susan: "P-u-s-h. 'I can't stand it, I can't stand it,' I hear someone -- myself? -- scream.

"Three forty-one P.M.: 'Look, here is your baby!' . . . But I can't. I only see black. I'm in another place. I don't even hear a cry.

"When I come back to life, a baby is being lifted toward me . . . I feel as if I'm the only one who was absent at her birth. Away in another country, a dark place beneath the sea. 'But she's so beautiful!' I say again and again. Michael and I kiss. Jessica's mouth moves like a little fish's at my breast. She's the color of a shrimp, her fingernails are seed pearls, her head glistens with wet curls. My beautiful water-baby.

"Later, I call my parents with the sweetest news I've ever shared: 'Mom, Dad, I had a little girl today.' "