BEYOND THE MANGO TREE by Amy Bronwen Zemser, 176 pages, Greenwillow, $15. (Read in galley proofs.)

Once in a while a book comes along with such imagery that it leaves the reader with a sense of having dipped into an artist's palette. That is Amy Bronwen Zemser has done with "Beyond the Mango Tree."First, the story is set in a colorful country, Liberia. Then the author sprinkles it with the hues of the rainbow and has thrown in the sights and sounds of a lovely melody as she spins a poignant plot as compelling as the orange spider on its web.

In a few beginning paragraphs, we are told that Sarina is tied to a tree with rain splashing around and puddles the color of rust-colored crumbled bricks. Her mother with clear blue eyes is having a reaction to low sugar and is unable to release her from the twine that binds her. The child is left to tormentors and is ultimately released by a strange boy whose "dark hands, unlike my own pale feet, do not seem to twitch at the fear of the unseen bottom" of the black pool of water. Zemser has captured us as readers!

This is an unusual novel; I know of no other for young readers that is set in this part of Africa, nor one where a mother is chronically dysfunctional because of a low-sugar reaction. Fictional daughters sometimes become the caregivers of their parents and, in this case, Sarina does it because her father is away as supervisor of a lumber camp in Nimba County. Sarina is virtually left to servants who guard the house, cook, clean and do the shopping. The trouble is that Sarina has no friends, does her studies by mail and cares for an overly dependent mother.

"Beyond the Mango Tree" could be a very troubling story, almost what we'd call a problem novel. But the author skillfully moves it beyond that with her descriptions of the characters, particularly Sarina, Boima, the native boy who rescues her and TeTe the irascible maid. One step further is how she paints the most exotic word pictures which is a real plus for young readers. For example, yellow is not just a color randomly used, it's the yellow fever ("a woman . . . beautiful but wilted, wasting slowly away as a sallow poison inks its way through her veins, leaking a yellow that stains her from the inside out") and it's also the color - "the simple, palest yellow" - of her mother's dress when she is well enough to dress herself. Too, Boima's voice is like pure yellow sunlight as he tells the stories of his people.

Color appears everywhere in this work. The day is not just misty, it's a "dusty grey morning" over a garden that has curled and unruly bushes. The shopping place is full of mar-ket-goers that "push in a damp wave of heat" along many tables piled with mounds of "candies in pinks and greens and blues" and fruits and vegetables of every color; green, red, yellow and orange. The cobra has "tiny eyes, so hard and black and a pink flickering forked tongue."

The authors uses sight and sound the same way as she splashes around color. The raindrops don't just hit the window. Instead "two clear drops of rain touch and unite on the window." Again she uses description when "a smile disappears from her face like a necklace down a sink drain." When Sarina's mother drops a blue porcelain bowl the "jagged pieces scatter across the white tiles like bits of sky through clouds. . . . " As Sarina and Boima swim in the lagoon they open their eyes "inside the quiet fluid of an inner world tinted green, where movement is beautiful because it is so simple. . . . " There are "grey streaks of finger-shaped bruises" on Sarina's arm.

In contrast to Sarina's mother whose body is thrashed by the sugar disease, Boima's mother has "eyes that light up with the pure, clean joy of living, of the richness of the colors of sun and earth and moon and rain. I have never in my life met anyone whose presence alone feels like such a cel-e-bra-tion."

What a joy this book is to read! The dialogue of Liberian English is handled so expertly where the sentences end with an emphatic oh!, for example, "you all kind of something-o." Sarina describes it as the language "that skims across the air like skipping stones on water." And so we read "What' you talk', small gal?" or "Never climb the mango tree by you one . . . he vex every time. . . . Keep all two you eye open."

Zemser also includes customs and rituals that make this an authentic story. Sarina finds particularly elegant the Liberian women who balance large baskets on their heads and their colorful lappahs or dress cloths. Their beliefs in genies and juju, the magic that makes people change, are all brought into the story through the wonderful young lad, Boima, who ultimately contracts yellow fever.

"Beyond the Mango Tree" is a tender, heart-wrenching story that is brilliantly written and will be enjoyed by students in grades five and up.

The author moved to Liberia in 1980 when she was 11 years old. She lived there for three years. She now works for City College in San Francisco, California, where she teaches English as a second language. Her dedication says "Africa is painted in my mind." She has painted it in the mind of the reader, as well.