FEW WRITERS of this century more de-ju 10.8 serve to be saved from obscurity than the three Powys brothers. Sons of a conventional British clergyman, the Reverend Charles Powys, and his imaginative, high-strung wife, Mary Cowper Johnson, the brothers were distant descendants of the poets John Donne and William Cowper--and even more distant descendants, they believed, of the ancient Welsh princes of Powysland. Growing up in Dorset in the late 19th century, they were influenced by the same wild, romantic heath country that inspired their friend Thomas Hardy. Like many sons of Victorian fathers, all three rebelled against their father's dogmatic Christianity, and each forged a distinctive philosophy--and art form-- to replace the beliefs he had lost.

John Cowper Powys (1872-1963), the eldest of his family's 11 children, embraced a pagan polytheism in which even seemingly inanimate objects possessed psychic energy, whether for good or evil. His vast, mystical novels--A Glastonbury Romance, Wolf Solent, Maiden Castle and Owen Glendower--are peopled with scores of characters and sometimes set in the distant past; his searchingly honest Autobiography, according to British poet Kenneth Hopkins, is "the greatest autobiography in the English language."

John's younger brother, Theodore Francis Powys (1875-1953), was a self-confessed "hermit" who rarely set foot outside his Dorset village. The most original thinker of the three, he denied the possibility of an afterlife and stoically accepted the cruelties of life on earth; his art took the form of allegorical novels and short stories full of ironic humor. In the novel that is generally considered his masterpiece, Mr. Weston's Good Wine, God comes to the village of Folly Down disguised as a wine merchant, meting out judgment to the townsfolk by selling them either the light wine of love or the dark wine of death. In Fables, a collection of his short stories, such unlikely characters as a dishcloth and a pan, a stone and a skull, and a bucket and a rope make homespun observations about the nature of life.

Llewelyn Powys (1884-1939), the youngest of the brothers, was a confirmed atheist. Stricken with tuberculosis when he was 25, his life became one long battle against the disease. Not surprisingly, he believed in seizing each moment and living it to the fullest. As a writer, he won fame for exquisitely crafted essays that conjure up the atmosphere of his surroundings --from the Dorset countryside of Earth Memories to the African jungle of Ebony and Ivory and Black Laughter.

In this first-rate biography Richard Perceval Graves, the nephew of poet Robert Graves, shows that he has mastered the voluminous materials written by or about the Powys family--including thousands of unpublished letters at Colgate University, Syracuse University and the University of Texas. He has entered the minds and hearts of his subjects, skillfully shaping his evidence to reveal the psychology of each man and the pattern of his life.

Graves presents three unique but related portraits. There is John as a young man, struggling to overcome his sadistic fantasies, his obsession with the boyish women he liked to refer to as "sylphs." Eventually, after an ill- advised and unhappy marriage, he would become popular as a flamboyant lecturer on literature in the United States, live an artist's life with Llewelyn in the Greenwich Village of the 1920s, and settle in Wales to study the myths and legends that animate some of his finest work.

We see Theodore, a gruff, earthy countryman for all his reading of Nietzsche, who married an uncultured village girl because, as he put it, "I don't want anything intellectual. I want little animals' roguery." With the help and encouragement of his brothers, he would persevere through years of poverty until his unorthodox talents were at last recognized, beyond even his wildest dreams. And finally there is Llewelyn, the handsome, reckless consumptive who seduced his fellow patients in a Swiss sanatorium and later managed a farm in the wilds of Kenya, just to reassure himself that he was still alive. The advocate of pleasure, his very real passion for his wife, the writer Alyse Gregory, was often at odds with his love for the beautiful poet Gamel Woolsey.

Graves has chosen to concentrate on the day-to-day concerns of the brothers--literary, financial and amorous --and downplay their literary work; he provides only brief descriptions of plots and characters and virtually no criticism. Also, he rarely steps back far enough from the brothers to give a sense of the literary reputation that each achieved in his lifetime, even though such details would certainly have illuminated the psychological portraits he has made.

But these are minor failings in a book that is full of riches. Graves' Powyses are so fascinating that one feels compelled to turn to their work, and The Brothers Powys offers guidance to help those unfamiliar with their writings decide where to begin. Like the works of the Powys brothers, this book deserves to be read and remembered.