YOUNG ADULTS, teenagers, whatever you want to call them ("older children" may be the best term) -- they're probably the hardest group of readers to snag, and the easiest to lose halfway through a book. Generally they're impatient, jittering to get on with their real lives. And the mere sound of an adult voice, even if it's only on paper, tends to make them sigh and roll their eyes.

The writer hoping to attract these readers has two choices. The first is to try to enter their world -- present it to them so vividly that they will sit up and take notice. The second is to pull them out of that world, using characters of the appropriate age but making no further allowances, trusting that effective writing and a strong plot alone will be enough to snare them.

Paula Danziger, in It's an Aardvark-Eat- Turtle World, has chosen the first approach. As an experienced teacher and counselor, she knows the intricacies of contemporary adolescent life, and she puts her knowledge to good use in this story about two best friends whose divorced parents fall in love with each other and combine their households.

Phoebe and Rosie will be familiar to admirers of The Divorce Express, in which the parents' romance first began to bloom. There, the romance provided the happy ending. Here, the happy ending is examined more closely and found to contain some flyspecks. How does a girl accustomed to sleeping in her own room adjust to sharing one -- especially with someone who doesn't like the same kind of posters on her walls? More important, how does she adjust to sharing a parent? Or how can she accept, overnight, the fact that a semi-stranger suddenly has the right to criticize her behavior? These issues are presented realistically and sympathetically. Paula Danziger is probably best known for The Cat Ate My Gymsuit, but I found It's an Aardvark-Eat-Turtle World superior, particularly in its avoidance of the black-and-white, good-guy-bad-guy aspects of some of her earlier books.

Peter Dickinson -- an English writer of thrillers for both children and grownups -- has chosen in Healer to draw his readers into a situation completely unlike the average teenager's. His central character is a 16- year-old boy who becomes acquainted with a lonely, fearful little girl named Pinkie. Pinkie once healed Barry's migraine headache simply by taking hold of his hands -- or maybe he only imagined she healed it; maybe the headache was about to leave anyhow. That ambiguity is what gives the book its tension, for Pinkie's stepfather eventually installs her as the spiritual healer in the "Foundation of Harmony," and Barry can't be sure who is exploiting whom, or how urgently Pinkie needs to be rescued.

Not your everyday problem, but it's both gripping and convincing, thanks to the fine writing. Peter Dickinson never talks down to his readers, and he knows that even a page- turner plot like this one can use a good sense of character. Barry is a troubled, kind, believable high school dropout; Pinkie in her thick spectacles is stolid and mysterious and elderly. You could find the two of them intriguing whatever your age.

M. E. Kerr has proved a good many times over (in books like Him She Loves? and Dinky Hocker Shoots Smack!) her skill in entering young people's worlds, but her latest offering takes a slightly more distant stance. I Stay Near You is a novel in the form of three stories. The first story, which is set in the 1940s, describes a love affair between the town's rich boy and a very poor, very strange girl named Mildred. The boy is killed in the Second World War and Mildred, who is pregnant with his child, marries someone else. In the second story, which takes place in the '60s, Mildred's son Vincent falls in love with an unsavory girl who eventually breaks his heart. And in the third story, Vincent's son Powell reflects upon his father -- now a self-centered, middle-aged rock star -- and comes to some conclusions about his own life.

An unsuitable romance is always interesting, and this one is no exception. But it's so thoroughly defeated -- and defeated so early in the book -- that you wonder if teenaged readers might drift away after the first of the stories. Moreover, there's something chilly and remote about the two lovers. As always, though, M.E. Kerr's crisp writing style is flawless, and she successfully avoids that gee-whiz tone so common to writers of young adult books.

Robert Newton Peck, author of A Day No Pigs Would Die and 30-odd other books, has set his latest novel on a cattle ranch in Depression-era Florida. Spanish Hoof describes a small makeshift family -- a widow, her young son and daughter, and two hired hands who are more friends than employees. These five struggle to keep from losing the ranch when times get hard. They're a likable, warmhearted bunch, particularly 11-year-old Harriet, the narrator, who's as spunky as Scout of To Kill a Mockingbird. The only problem is the language Harriet uses to tell her story. It's dialect in the extreme, and although it may be perfectly authentic, it sounds forced and is often difficult to understand. Will skittish readers stick with this book in spite of all the dropped g's and nouns-turned-verbs and adjectives-used-as- adverbs?

Well, what makes them stick with any book is anybody's guess. But they do have a good array here: one from their own world, three others from worlds more distant, each with a special kind of allure.