By the end of this year, more than a million children's parents are going to get divorced. No surprises there, but until I read Linda Francke's enlightening book, "Growing Up Divorced," I had no idea of the havoc GROWING UP DIVORCED. By Linda Bird Francke. (Linden Press/Simon & Schuster. 303 pp. $15.95) that these marital breakups will wreak in each and every one of those children's lives.

Even Francke, a divorced mother of three, was surprised by the pain and anger and bewilderment her own children experienced when she and her husband separated. And when she began the interviews that form the core of "Growing Up Divorced," she was shocked anew by how universal her kids' reactions had been. "They were just ordinary children, these kids, from a five-year-old in a starched eyelet dress to a cool teen-ager who resented the time spent out from under his Walkman," she writes. "But what they had to say about divorce was filled with articulate doses of resentment, resignation, hope, courage, cynicism and contempt. Two emotions were predominant. Almost all of the approximately 100 kids I talked to expressed sadness. And virtually all of them were angry."

While their parents are going through the painful, three-year crisis that Francke says divorce inevitably precipitates, their children face more than a three-year struggle: their entire childhoods, and perhaps even their adult lives, have been irrevocably altered by the fact that their parents' marriage has ended.

These children will undergo changed economic status (single-parent families are poorer than two-parent families, and more than half the mothers who are legally awarded child support do not get it from their ex-spouses). Their social lives will be affected as well, because divorce, unlike death, Francke points out, isolates families when they most need support from relatives and friends. Their school lives will change, too, as even young children either cling to or reject teachers, schools and friends in their search for structure and affection. Many of these children will not only feel angry, lonely and frightened, but some of them will actually make themselves sick or have serious accidents to get the attention they need, which their parents are often too preoccupied to give.

So what's a parent to do? There's a great deal that divorcing parents can do to mitigate the worst effects of divorce, Francke writes, even much that angry and emotionally paralyzed adults can do to keep their children's rocky adjustment period from turning into a damaged lifetime.

"Growing Up Divorced" is so sensibly and warmly written that it should be accessible to even the most defensive or frightened divorced parents. Francke does not just outline the horrors of divorce, her purpose is to help parents cope. Each of Francke's chapters on the ages and stages of divorce--Infants: The Age of Helplessness; Preschoolers: The Age of Guilt; Children 6-8: The Age of Sadness; Children 9-12: The Age of Anger and Teen-agers: The Age of False Maturity--ends with a section entitled "How Parents Can Help."

One of a spate of fascinating books on the stresses of childhood that have come out during the past two years, "Growing Up Divorced," such as David Elkind's "The Hurried Child" and Marie Winn's "Children Without Childhood," not only signals an end to a peculiarly adult-oriented decade and a half (from the late '60s to the early part of this decade) but is part of the new generationalism--a view of children as vulnerable creatures, immature and impressionable, who need adult understanding and protection.

Sympathetic to parents' problems, Francke takes the overwhelmed mothers and fathers by the hand, as it were, and lets them get a painful glimpse of their children's fear and confusion. Then, quickly, before this terrible new knowledge can simply become another unendurable stress, she shows them how to talk to their children, tells them how they might deal with an angry ex-spouse so that the children don't become pawns, helps them cope with schools, friends, coworkers--all the people and things who could be supports, not impediments, to their children's finding the love that, she writes, is all they want, after all.