From my days as a resident in pediatrics, I remember milk bags on a shelf in the freezer in the nursery. Not bottles. Bags, tiny plastic bags with labels bearing the names of one or another premature infant whose mother was doggedly pumping her breasts to provide a tenuous lifeline to her tiny offspring. The frozen ounce or two was thawed on schedule by a nurse and fed to the infant, completing what is surely one of the most arcane and committed acts of mothering known to the species.

As an exercise in parenting filtered through science, maternal milk-banking is a symbol of our times. Not only do we have the capabilities of collecting, storing and delivering the milk, but the survival rate of the nation's nearly 250,000 "preemies" (infants weighing less than 2,500 grams--5 1/2 pounds--at birth) born annually has improved steadily. Many infants who would have died in earlier years now survive, living for weeks and even months as guests of the neonatology service--a crucial, life-sustaining internment that takes place, for the most part, beyond the reach of parents.

The result is a new kind of parenthood for thousands of couples, parenthood confounded by the surprise of early birth, the worry of a sick child, the confusion of a sudden, forced introduction to a staggering world of hi-tech medicine, and the frustration of physical separation from the object of parental love--the baby itself. "Born Early: The Story of a Premature Baby" and "Your Premature Baby" stand as two enormously valuable contributions to the emerging literature of preemie parenthood.

"Born Early" is written by Mary Ellen Avery, the physician-in-chief of the Children's Hospital Medical Center in Boston, and punctuated by photographs by Georgia Litwack. It is a slim volume that traces the birth and growth of Adrienne Weber, an infant delivered almost four months early weighing 710 grams (1 lb. 9 oz.), who struggles gamely through 16 weeks of life in the nursery before going home one week after what would have been her mother's due date. Adrienne encounters an alphabetic onslaught of diseases including RDS (Respiratory Distress Syndrome), NEC (Necrotizing Enterocolitis), RLF (Retrolental Fibroplasia), and PDA (Patent Ductus Arteriosus). She endures these challenges to her life and prospers, providing Avery and Litwack the opportunity to record her progress from incubator to crib to home.

The book is written in a gently authoritative style that never patronizes, yet it has a definitive and experienced tone. The story has moments of candor that surely will be helpful for many preemie parents who are experiencing periods of disagreement or frustration with the nursery.

Adrienne's mother, who supplies breast milk on a daily basis, is told "to her great dismay and anger" that she must stop because her blood reveals a positive test for hepatitis. The crisis is resolved when the infectious disease consultant reports that there are no documented cases of hepatitis transferred in breast milk, so Adrienne's mother resumes supplying milk. But "anger and dismay" can be part of the preemie parents' world, and "Born Early" does well to acknowledge it.

"Your Premature Baby" is a much more thorough treatment of prematurity. Written by Robin Marantz Henig, a Washington science writer, and Dr. Anne B. Fletcher, chief of the Neonatology Unit at Children's National Medical Center, it systematically and readably examines a preemie's first year of life.

The book features sections on such issues as the reaction of other children at home (with a comic book section called "My Sister's Too Small to Come Home") and the special problems of raising a preemie. The appendixes include a glossary of neonatal terminology and a state-by-state list of organizations for the parents of preemies. The book's final chapter raises a number of important--if not always resolvable--issues about our society's neonatal capability.

If I have a quibble with these two fine books, it is this: The most painful burden of prematurity is borne by the parents of infants who do not make it and, perhaps toughest of all, by parents of preemies who live but with significant impairment. A bit more attention to the frustrations of failure and the agonies of adjusting expectations downward would have been helpful.

Gone are the days that I knew as a resident when the parents delivered their milk and glimpsed their tiny child through the glass of the nursery window and the plastic of the incubator. Today's parents of preemies and today's nurseries are much more involved with one another. These two volumes are tremendously useful road maps for the journey that the parents of all premature infants must take.