YOU HAVE TO BE a little crazy to try to do good work in science fiction, a field where indifferent, run-of-the- mill, lowest-common-denominator work is often not only tolerated but actively rewarded, and where good work is often not only ignored, but, in many cases, greeted with outright hostility. About the only thing that has saved sf, kept it evolving, is the constant influx of new writers, writers young and enthusiastic enough to actually work harder than they need to for the same kind of money they'd have gotten for producing a formula space opera. Eventually, many of them burn out, wear themselves smooth, get tired and cynical, and opt for the easier way. But sf has so far been lucky in always having a new generation of writers -- roughly every five to 10 years -- waiting to snatch up the torch (with naive enthusiasm, of course) as the previous generation lets it slip from numbed hands.

At the beginning of the '80s, we are clearly in the process of assimilating yet another generational wave of hot new writers, and in the years to come you will be hearing a whole lot more about William Gibson, Michael Swanwick, Kim Stanley Robinson, Bruce Sterling, Greg Bear, Pat Cadigan, John Kessel, Lucius Shepard, Lewis Shiner, Connie Willis, James Patrick Kelly, Leigh Kennedy, John M. Ford, Tim Powers, David Brin, and Pat Murphy. . . to name just some of the most prominent of those on the leading edge of this massive generational wave.

Not all of these writers are of the same esthetic school or movement, by any means. Many of them don't even much like each other's work. (About the closest thing here to a self-willed esthetic "school" would be the purveyors of bizarre hard-edged, high-tech stuff, who have on occasion been refereed to as "cyberpunks" -- Sterling, Gibson, Shiner, Cadigan, Bear.) Nevertheless, they are the '80s generation in sf, or part of it, and whether they like it or not, the similarities in goals and esthetics between them are much stronger and more noticeable than the (admittedly real) differences. For one thing, they are all ambitious writers, not satisfied to keep turning out the Same Old Stuff. Once again it is a time for literary risk-taking, and once again those who take them are admirable -- and that makes it an exciting time for sf as a genre.

Some of these new writers you may already have heard of: William Gibson's Neuromancer and Kim Stanley Robinson's The Wild Shore, both part of the revivified Ace Specials line, were probably the most widely-acclaimed and talked-about first novels of 1984; Greg Bear took two Nebula Awards and a Hugo Award this year for his short fiction, as did Connie Willis for her's the year before; Lucius Shepard has had strong short storiecoming out all over the magazine market this year, in addition to his flawed but still impressive first novel Green Eyes (Ace Special); David Brin won both the Nebula and Hugo this year for his novel Startide Rising (Bantam) . . . and so on. Light Years and Dark

NOT SURPRISINGLY, many of these same writers provide much of the first-rate work in Michael Bishop's enormous new anthology Light Years and Dark (Berkley, $8.95).

This is a big, meaty book, containing a rich diversity of material, both reprint and original -- the anthology contains 40 stories, four poems, three short and very funny parodies of other sf writers by John Sladek, and an autobiographical fanzine article (!) by James Tiptree Jr.; its 18 original stories alone make it the largest original sf anthology of 1984, and one of the largest of recent years. Light Years and Dark is a retrospective collection, covering the evolution of sf from 1960 to the present, and as such provides a good sweeping overview of the changes that have been taking place in the field during the last 20 years. It is to be especially commended for featuring fine reprint stories by first-rate authors such as Robert Thurston, Steven Utley, Barry Malzberg, Gregory Benford, Christopher Priest, and others (including Bishop himself) who are usually overlooked in the assembling of "retrospective" collections such as this. (Among the reprint stories, note particularly three rare gems: Tom Reamy's chilling "Under The Hollywood Sign," Jack Dann's bizarre and unsettling "The Dybbuk Dolls," and Thomas M. Disch's brilliant "The Death of Socrates," which in light of recent work, shows just how far ahead of his time Disch was in the early '70s when he was turning out the stories collected in 334.)

The original stories here are uneven -- some of them strike me as pretentious rather than profound; some of them are very good indeed. Gene Wolfe's "The Map," a story set in his Book of the New Sun universe, and Pat Cadigan's incisive and hard-edged "Rock On" -- the most impressive story to date by this extremely promising new writer -- are probably the best original stories here. They are followed closely by Kate Wilhelm's "Strangness, Charm and Spin" which is not really sf -- unless you go for the rather weak justification that it's about probability theory -- but which is warm, human, and moving, John Kessel's quietly surreal "The Lecturer," Michael Swanwick's intricately-plotted, time-travel yarn "When the Music's Over," Ian Watson's exploration of a bizarre afterlife "The Bloomsday Revolution," and M. John Harrison's strange and haunting "The Lords of Misrule"; there are other good stories here, but these are the cream of the crop. They are all quiet stories, subtle stories, and probably none of them is flamboyant enough to make it onto this year's award ballots -- but that's not a reason why you shouldn't read them. Oh no. Quite the contrary, in fact.

Light Years and Dark is so big that it's easy to find things to dislike about it. As an anthologist, I found some of the choices of reprint material eccentric: why reprint "Terrific Park," one of George Alec Effinger's weakest stories, when so much good Effinger material remains unanthologized? Why a fanzine article by Tiptree, rather than one of her groundbreaking and highly-influential short stories? Why nothing by Samuel R. Delany or Joanna Russ or John Varley, writers much more important historically to the genre than some who are included?

But ultimately these are quibbles. Light Years and Dark succeeds because of its scope and eclecticism -- there is such a diversity of themes and styles in the book that there is certain to be something here to appeal to almost every taste. Hiroshima and Beyond A

AT ONE TIME, only a few years ago, there were a number of annual original sf anthology series -- rbit, New Dimensions, Destinies, The Berkley Showcase, several others. Now almost the only one left is Terry Carr's Universe series. That's the bad news. The good news is that Universe is not only still alive, but is also better than ever.

Much of the quality work in recent volumes has been supplied by new writers (Carr's track-record for discovering new talent is very good indeed), and Universe 14 (Doubleday, $11.95) is no exception.

There are three major stories here, really first-rate work, and several good ones. The best story in the book is probably Kim Stanley Robinson's "The Lucky Strike," an alternate World War II story about a universe where a crew other than the crew of the Enola Gay ends up flying the bombing run against Hiroshima, with some fascinating results. It's a magnificently executed piece, with some excellent characterization -- particularly that of the protagonist, January -- and a good deal of genuinesuspense. Perhaps the fact that the author definitely has a political ax to grind shows through a little too clearly at the end, but this is still a major story, certainly one of the year's best.

Rivaling the Robinson story in quality is Lucius Shepard's "Black Coral," a taut, gritty, and genuinely nasty story about an Ugly American type who has a confrontation with otherworldly forces on a tiny Caribbean Island; most sf writers are very unconvincing in their descriptions of mean streets and sleazy backwaters, but there is an authentically bitter bite to Shepard's low-life stuff, and "Black Coral" is riveting. The other major story here is Molly Gloss' "Interlocking Pieces," a quietly effective tale, rather reminiscent in style of middle- period Le Guin, that builds surely and economically to a moving conclusion.

Below these are several good but flawed stories: Carter Scholz's rather humorless "The Menagerie of Babel," Sharon N. Farber's ambitious "Passing As a Flower Through the City of the Dead," and Joel Richards' routine time-parodox tale, "Deadtime." Pat Murphy's "Art in the War Zone" is expertly crafted (Murphy is one of my favorite short story writers), but I spent too many years in the Army to believe for a moment in her depiction of how a group of pacifist artists are able to defeat a ruthless invasion force by playing mind-games with them; this is a variant of what Damon Knight calls the "idiot plot" -- it only works because the commander of the invading army is an idiot who apparently has never read a book on guerrilla warfare or counterinsurgency, and because the author stacks the deck heavily in favor of the pacifists. Time Travel with Pizazz

HOWARD WALDROP stands in a vaguely avuncular relationship to some of the new writers, particularly the Austin-centered "cyberpunks." Waldrop doesn't often write high-tech stuff himself, but surely the wild and woolly "outlaw fantasy" Waldrop began producing in the mid '70s played some part in shaping the esthetics and literary style of the "cyberpunk" movement, and his work has also been influential on some of the other new writers as well.

One of the genre's finest short-story writers, known for his strong shaggy humor, offbeat erudition, and bizarre fictional juxtapositions, Waldrop brings all of these same qualities to his first solo novel, Them Bones (Ace Special, $2.95). A wild and recomplicated tour through both past and alternate worlds, Them Bones brings to the time-travel yarn the sort of pizazz, offbeat ,elan, and gritty vigor that has been largely missing from it since G.C. Edmondson's 1965 classic The Ship That Sailed the Time-Stream. Waldrop's picture of an alternate America where Arabs in paddlewheel steamboats cruise the Mississippi to trade with Moundbuilder Indians (the Roman Empire fell to Carthage and is no more, but in the south the expanding Empire of the Aztecs is an ever- growing threat) is genuinely fascinating, with the social dynamics of the Moundbuilder culture worked out in particularly interesting detail. Waldrop even finds room in the picture for a few woolly mammoths.

I regret that the mechanics of the rest of the plot -- for this is only part of what's going on in this novel -- prevented this alternate timeline from being explored in greater detail; I badly wanted Madison Yazoo Leake to get on that paddlewheeler with the Traders and chug off to see the rest of this intriguing new world, and was sorry the book ended before he got a chance to do so. In fact, if there's any real flaw in the novel it's that it's rather short -- a fault exacerbated by the fact that later installments of one of the interlacing subplot sections ("The Box") begin to look suspiciously like padding. But there is so much happening so quickly and so colorfully in Them Bones that I doubt many readers are going to notice, or care, and the novel should help to bring Waldrop some of the attention he deserves; certainly he has one of the most vivid and original imaginations in this or any other field. Gardner Dozois edits the annual series "The Year's Best Science Fiction." His story, "The Peacemaker," received the 1983 Nebula award for best short story.