Although it is clearly aimed at adopted children, there is much in this book to interest anyone interested in families and the place of children in them. Jill Krementz, the author/photographer well-known for her chronicles of young horseback riders, dancers, skaters, etc., here and in her recent How It Feels When a Parent Dies, turns her lens away from the world of child glamour and gets down to the nitty- gritty. There is strong stuff in these pages about what adoption means. Krementz, in her choice of candid and sensitive children to speak their minds on the subject, demands that her readers face important issues--especially the issue of biological parents and the possibility that they or the child might one day want to search for each other.

For several of the children in this collection of portraits and first-person narratives, the discovery of biological mothers has already occurred. The experience was positive for one 13-year old girl, whose adoptive mother helped her search. "I felt more worthwhile in the world--as though I belonged better," she says. But for others the experience can be emotionally traumatic. One wonders, in fact, at the judgment of two birth-mothers in the book who themselves initiated contact with their teen-age daughters, for whom the meetings have brought complicated feelings. Says 15- year-old Holly, "The past two years have been real hard on my parents. I get the feeling that sometimes they're thinking that they're losing me, and that's the last thing in the world I want them to feel."

But most of the children in Krementz's book are not beset by such turmoil. They live fairly ordinary lives; yet they seem particularly perceptive, articulate, and sensitive--very conscious of their place in the family, their importance to their parents. And they nearly all have a healthy curiosity about their birth-parents, although not all envision ever searching for them. There is great racial and ethnic variety among the children, just as there is among the adoptive parents in the book. The majority are middle-class couples. But Krementz also included a single man who has adopted five sons, and a single woman who adopted a Korean daughter, and a black priest with an adopted son. Surely the most exceptional story is that of Gayle, 14, whose widowed mother at 71 cares for four adopted children, including two handicapped sons.

Along with the theme of biological parents which runs through Krementz's book, there is also the one of rejection, or fear of it. Not all these boys and girls were adopted as infants. Several remember being in foster homes or have memories of biological mothers who could not keep them for one reason or another. And a couple talk about their first visits with the families which eventually adopted them-- about their anxiety that they would not be "accepted." Yet all now seem secure; or if they aren't, they seem to know why. "I've never had real parents until now and it's hard for me not to feel a little insecure if one of them isn't around," says Melinda, age 10.

How It Feels to Be Adopted is a beautiful book and an honest one. In her photographs Krementz makes sure these children look real, not precious, and what they say rings with sincerity. SO YOU'RE ADOPTED, by Fred Powledge (Scribners, $9.95. Ages 12-up).

Krementz's and Fred Powledge's books make a complementary pair. While How It Feels lets children talk about adoption, So You're Adopted deals with the history and the "issues" of adoption in a frank and straightforward way.

Powledge, who is adopted himself, knows that adopted children, especially as adolescents, are often curious about the past, and sometimes uncertain about the present. In a reassuring, almost avuncular way, he sets out to explain, allay fears, and give advice.

He relates the history of adoption, which at one time was almost like indentured servitude for the child. He writes about the changes in adoption: reasons for the dwindling numbers of healthy children available to prospective parents, the growing emphasis on honesty with adoptees. And he addresses the "big" issue today--the search for biological parents. Powledge takes a dim view of the militants, especially those who contend that adoptees are not "whole" until the search is complete. And he makes a convincing case that searches should be made only by adults, not by adolescents.

That piece of advice, like most of what is in this little book, is clear-eyed and refreshingly honest. What Powledge has to say speaks well of his own experience as an adopted child. DAWN DARING, by Caroline Jackson, illustrations by Bethann Thornburgh (Belvedere Press, $10.95. Ages 3-6).

Dawn Daring is an independent-minded star, not content to hold a place in the Milky Way. After a childhood spent sliding down rainbows and dancing around the sun and moon, stationary life offers few diversions. So Dawn Daring becomes a kind of professional Good Samaritan, and in two adventures rescues first a spaceship which has lost its lights and later a baby star who falls through a hole in the moon.

The story is full of whimsy and sheer glee-- conveyed as much through Bethann Thornburgh's charming illustrations as through the narrative itself.

SINGING BEE! A Collection of Favorite Children's Songs, compiled by Jane Hart, pictures by Anita Lobel (Lothrop, Lee & Shepard, $16.50. All ages). Jane Hart has succeeded beautifully in her intention to provide a book of music for children to sing, play and dance to. Her choices of songs, which include a variety ranging from "A Hunting We Will Go" to "El Coquito" and "Eletelephony," is clever and lighthearted. Her arrangements are simple enough for a beginning piano student to play, and she even thoughtfully notes guitar chords for the tunes.

But what raises this songbook from "successful" to "super" is the brush of Anita Lobel. For a songbook, Singing Bee is heavily, and happily, illustrated, but never overwhelmingly so. Lobel, winner of the 1982 Caldecott Medal for On Market Street brings to life these 125 traditional and folk songs with scenes and figures out of the 18th century when people first sang them.

It's always a pleasure to meet a book conceived and made with thoughtful consideration for its audience. Not only is this one beautiful. It will even stay open on the piano.