Exquisitely illustrated 'Hiawatha'; Hiawatha, by Henry Wadsworth Longfellow, pictures by Susan Jeffers. New York: Dial Books for Young Readers. E. P. Dutton Inc. Pages unnumbered. $11.95.

Generations of children have delighted in the sounds and imagery of ''Hiawatha's Childhood'' since it was first published in 1855. Of course, it is part of Henry Wadsworth Longfellow's longer epic poem about American Indians, ''The Song of Hiawatha.''

Now, Susan Jeffers, an award-winning illustrator, has produced a dramatic, oversize picture book to accompany Longfellow's verse. It's hard to find one word to describe the double-spread illustrations where only a small space is devoted to the verse. The currently overused ''awesome'' may say it best.

The poem, a childhood favorite, continues to please me and stir my imagination. I can still hear the pines whispering and the lake water lapping when I read it aloud. And in my mind's eye I can see the wrinkled, moccasined grandmother gently teaching the little boy the Indian ways.

Susan Jeffers has captured the wonderment of Indian life and legend through well-researched drawings. For the full color artwork, she has used a fine line pen with many colors of ink and dyes. The effect is exquisite.

When little Hiawatha sees a rainbow and asks, ''What is that, Nokomis?'' Nokomis answers:

'''Tis the heaven of flowers you see there; All the wild-flowers of the forest, All the lilies of the prairie, When on earth they fade and perish, Blossom in that heaven above us.''

Ms. Jeffers devotes the center-spread illustration to a beautiful summer day with a small Hiawatha and Nokomis picking wildflowers against a backdrop of distant hills with a rainbow overhead.

But more striking are the scenes depicting the lessons Nokomis taught: shadow warriors of myth and legend silhouetted against the starry night sky, fireflies flitting in the twilight, the owl and owlets of the forest darkness, and the shadows on the moon.

Other scenes show the Indian village with its bark wigwams, a variety of colorful birds which the boy called ''Hiawatha's Chickens,'' and the animals which he came to know so well and call ''Hiawatha's Brothers.''

A novel addition to the book is Ms. Jeffers use of the endpages (inside the front and back covers) to frame the story. She uses the front to illustrate Nokomis falling to earth and the back to show Hiawatha's stepping into manhood, to suggest the larger scope of Longfellow's poem.

Reading ''Hiawatha'' sent me to the bookcase to look for the longer version. I hope young people, parents, and teachers reading this book will do the same. It's a wonderful epic which you want to pass on to a new generation.