THE 1980s will be remembered in the world of science fiction as the time when the series novel -- from Gene Wolfe's critically acclaimed Book of the New Sun to Piers Anthony's best-selling "Xanth" books -- became the field's dominant form. Perhaps the most recognizable brand name in the sf series marketplace is that of Frank Herbert. The first novel in his "Chronicles of Dune" series, Dune (1965), has sold over 12 million copies in all editions and last year was turned into an extremely expensive motion picture. Dune's sequels, from Children of Dune (1976) onwards, have been national best sellers; the sixth Dune novel, Chapterhouse: Dune (Putnam, $17.95) is one of the few sf novels to land on the best-seller list immediately after publication.

Yet much has changed in the Dune universe in the 20 years since Herbert began the series. Those readers whose familiarity with this series ends with the original novel will be surprised to learn that all of the major characters in the first book have long since vanished, and that the vigorous political intrigue of Dune has been replaced by galactic conflict between two competing nunneries.

For, while the planet Arrakis no longer exists (having been blown up at the end of Heretics of Dune, 1984), what survives is the Bene Gesserit sisterhood, which so completely resembles a nunnery that the head of it is a Mother Superior and trainees are postulants.

Chapterhouse: Dune is, in a sense, two novels. On the surface it is another novel of galactic intrigue, describing the conflicts between the Bene Gesserit and the Honored Matres, another sisterhood devoted to dominance over the universe. However, unlike Dune, most of the action takes place offstage; none of the momentous events (space battles, planetary destruction) are directly experienced by the central characters. It is almost as if Herbert had inserted these battles as a minimum daily requirement for readers starved of action.

For in Chapterhouse: Dune, Herbert has written a Bildungsroman in which a young nun, Darwi Odrade, comes of age by learning not only her own sexual and social identities, but also the fundamental knowledge of the hierarchies of the universe. Herbert curiously assumes that most of the religions of the 20th century have survived relatively unchanged for 50,000 years (an assumption not made in Dune) and thus Christians, Zen masters, and even a wandering rabbi compete for Odrade's attention. As she achieves cosmic knowledge, the Bene Gesserit feverishly work at rebuilding Dune.

Dune, despite an overly familiar plot ("King of Kings with sandworms," according to short-story writer Harlan Ellison) succeeded in depicting an exotic and enchanting world. Much of the skills used in writing that book have been lost; Herbert is more interested in relentlessly explaining his philosophies than in the basic task of storytelling. Here is a sample:

"Important things happen but some people never notice. Accidents intervene. You are not present at episodes. You depend on reports. What good are reports? History in a news account?"

Whatever this proverb may be, it is certainly not the timeless wisdom of a sage.

Readers who have enjoyed the first five Dune novels will certainly enjoy the sixth. Readers who have skipped the previous sequels to Dune should certainly skip this one.

OCCASIONALLY a multi-volume sf novel emerges which, in its richness and density, is more than the sum of its parts. Wolfe's four-part Book of the New Sun is one such work; Brian Aldiss' Helliconia trilogy is another.

Like Frank Herbert, Aldiss has been writing sf for over 30 years; unlike many writers of his generation, he has strengthened, not declined, as his career progressed. Helliconia Winter (Atheneum, $17.95) is one of Aldiss' finest novels.

Aldiss' trilogy describes a year on Helliconia, a planet closely watched by human observers. Because each year on Helliconia equals 2,500 years on earth, Aldiss describes the birth and death of a civilization.

The world of Helliconia Winter is one whose culture is about to die of cardiac arrest. Winter is encroaching, which will leave Helliconia encased in ice for 700 years. The oligarchy which rules is gradually succumbing to a cultural winter, making increasingly arbitrary decisions which, while designed to protect the people, in fact push Helliconia further down the path of ecological suicide.

Aldiss' hero, Luterin Shokerandit, begins the novel as a naif, a gentleman farmer whose only worry is tending his crops and marrying his assigned bride. He ends the novel an embittered man, pushed through devastating years in the army, a gloomy quest through the northern ice, and imprisonment in the Great Wheel, a structure so vast that it takes 10 years to complete a revolution.

Like the finest science fiction, >Helliconia Winter is rich in scientific speculation, weaving insights from biology, linguistics, and physics into a rich tapestry. Yet Helliconia is more than a superb sf novel; its depth and elegance ensure Brian Aldiss' place as a major novelist of the 1980s.

Roger Zelazny is part of the generation of sf writers that came of age in the late 1960s. Indeed, Zelazny's first novel,This Immortal, tied with Dune for the Hugo award for the best science-fiction novel of 1965. Although Zelazny produced several important books in the late '60s, the best of which is the Nebula-award winning Lord of Light (1967), Zelazny has declined into an interesting fantasy novelist of the second rank.

Zelazny's longest series is the Chronicles of Amber, of which Trumps of Doom (Arbor House, $14.95) is the sixth volume. Unlike the Dune series, the first five books in this series were conceived as a unit, detailing the complicated intrigues of Amber, an alternate universe in which nine princes persist in ornate games of political intrigue throughout an elaborate fantasy universe.

At his best, Zelazny is one of sf's finest stylists, and what is impressive about Trumps of Doom is its cool tone, Chandleresque in its wry depictions of contemporary Albuquerque, where Merle Corey, computer programmer, is handed a mysterious pack of cards. He knows that these cards have some connection with men of mystery who are determined to kill him every April 30. As he begins to study what forces gave him the cards, he learns that the cards can transport him into Amber, where he discovers that he is not really Merle Corey, but Merlin, son of Corwin, the reigning prince of Amber who has disappeared to parts unknown. Merlin/Merle spends the remainder of the novel alternately fleeing across the suburbs of Albuquerque and spending time in Amber meeting long-lost relatives who scowl at him.

Trumps of Doom is not a complete novel in itself, but a fragment of a longer text. In the years before series became so common, it would have been the first three chapters of a novel. Indeed, at the end of this book, we do not know where Corwin is, who the villains are, or the limits to his powers. We do learn about the Ghostwheel, a computer software program designed to codify magic in Amber, and, in the most entertaining section, how to confuse a sphinx with a truly tasteless joke. "Somewhere there must be a gap in the icy blue logic that surrounds me," Merlin cries at the termination of Trumps of Doom, "against which I hurl my mind, my cries, my bitter laughter." Readers should wait until the remaining two Amber novels are published before hurling their minds into this text.

PHILIP JOSE FARMER has specialized in series over the years; at one point in the mid-'70s, he had seven in various stages of completion (most notably the "Riverworld" sequence). In Dayworld (Putnam, $16.95), Farmer begins a new series set in the 35th century.

As a population control device, citizens are forced to live only one day out of seven. The remaining six days, people are "stoned" -- placed in storage and forced to hibernate while other personalities take over their body. Thus seven personalities are able to occupy the space of one, solving the main problem of overpopulation.

However, "daybreakers" exist -- outlaws who, with the aid of life-extending drugs, are able to live beyond their assigned day. The hero of Dayworld, Jeff Caird, is a daybreaker who has created seven separate personalities in order to live life to the full. When the state learns of this, they send their agents chasing after Caird, who flees from day to day and from world to world until an inconclusive conclusion.

Dayworld is surprisingly dated; it reads as if it were a pastiche of the social-science fiction novels of the 1950s, in the traditon of Frederik Pohl and Cyril Kornbluth's The Space Merchants. On the surface Dayworld is a gritty chase thriller, complete with relentless scenes in the abandoned New York subway tunnels. Beneath the surface, Farmer is writing a satire of contemporary American life, but Farmer's targets have lost their relevance. For example, Friday's hero is Wyatt Repp, a writer of westerns whose chief problem is his sexual potency ("Fire me like a six-shooter!" says one female admirer). While Dayworld will not be remembered as one of Farmer's best novels, it certainly is an entertaining, if peculiar, adventure.