THERE ARE, OF COURSE, seasons among the stars. The supposed void of outer space in fact teems with tiny molecules swirling about in response to photon winds and gammaray showers. Over the millenia, we are told, these settle out and become the seeds of life. But such cosmic rhythms demand a very long patience indeed. Not many SF readers, paradoxically, are thus tempered.

Fortunately, the paperback publishers, running on their busier terrestrial clocks, have wasted no time. The racks are freshly in bloom with something for every science-fictional taste that may have been a-nurturing among the cabin malaises of dark February.

Those who have been waiting for C.J. Cherryh's next table of high adventure and swashed bucklers have a particular treat awaiting them with her Well of Shiuan . Not only is it the pure science fantasy quill, with its roustings of mailed warriors and its tense deeds among the battlements of fortresses never erected on this Earth, but it is the promised sequel to her 1976 first novel, Gate of Ivrel.

The well, like the gate, is a spacetime passageway between worlds. Each world is inhabited by humans, but also by the humanoid ancient qujal , who are very cold of heart, and possessed of certain secret ways. Through the gates, world after weary world, comes blonde Morgaine, the enigmatic warrior woman, followed by outlaw princeling Nhi Vanye i Chya. She carries the fantastic sword which can swirl armies into oblivion and, more important, unlock and then shut the gates forever behind her.

Cherryh is the best writer of this sort of adventure tale since the earliest days of C. L. Moore and the prime of Leigh Brackett. Morganie and Vanye fans will be fascinated by this new skein of development in the relationship between the two, as well as by the setting of her tale, so much like Ivrel and yet so different. Any reader who is willing to become lost in alternate reality will find much to enjoy, and will take pleasure in Cherryh's explicit promise of further stories.

Fans of superscience - casually definable as the almost abandoned art of proposing some fundamental scientific breakthrough whose subsequent rapid technological applications allow a few right-minded physicists and engineers to make overnight sweeping changes to how things are - will have an appropriately breathless time with James P. Hogan's The Genests Machine . There has been nothing like this in SF since the days when John W. Campbell, Jr., was writing The Mightiest Machine and The Moon is Hell out of the boundless technocratic optimism of the 1930s. Forty years later, the sub-genre is back again, appropriately at the hands of a gifted amateur with limited storytelling qualifications. Some will love it a great deal.

It was Hal Clement, more than any other SF writer, who made something more sophisticated and more literate out of superscience. He did it particularly with such novels as MIssion of Gravity , which introduced the courageous, resourceful Mesklinite race. Eighteen-inch centipedes accustomed to fearful pressures and unthinkably high gravity on their home world, the seafaring Captain Barlennan and his crew of traders are among the most "human" characters in science friction qua science Fiction. In the newly reissued 1971 sequel, Starlight , Barlennan and his confreres are under contract to humans, exploring the giant world Dhrawn and encountering meticulously worked-out perils in the process. While not as satisfactory a story as Mission , this one nevertheless meets a rigorous standard.

Marin Caidin, the technology popularizer and occasional novelist - Marooned, Cyborg (which led to the Six Million Dollar Man TV series), etc. - has now produced Aquarius Mission , clearly an idea for a pilot film. As essentially implausible as Cyborg , but, it possible, worse written, this book will probably sell a great many copies. Its deep undersea race of essentially humanoid people - they have gills, but somehow that makes the females only more attractive to the crew of the U.S.S. Sea Trench , and webbed hands which couldn't possibly work - is a ridiculous supposition. That has never stopped Caidin from selling in the past, and I am prepared to bet on his track record again.

Night's Black Agents , a collection of Fritz Leiber short work, is an outstanding bargain. Leiber is famous for being neglected. That is to say, periodically a critic discovers that this still-active master storyteller has been consistently ahead of his time over a very long career in SF. What matters truly is that, whether as a traditional fantasist, or a sword-and-sorcery writer, or an artist of "straight" science fiction, Leiber is unfailingly entertaining on a very high level. An updated, larger version of an early collection originally published by a small specialist house, Night's Black Agents is a sampler of Leiber at his best, and of the best that SF can attain in many of its modes.

The Best of L. Sprague De Camp is forthcoming in May and is available now as a Nelson Doubleday hardback from the SF Book Club. A triumphant collection from SF's best-educated humanist, this selection of De Camp's witty, very literate fantasy and science fiction tells you, among other things, precisely what sort of firearm to select when on safari for Tyrannosaurus Rex, and why webbed hands are useless for swimming. (A mermaid demonstrates).

For students of literature, and academicians generally, Oxford's second edition of H. Bruce Franklin's Future Perfect: American Science Fiction of the Nineteenth Century is a meticulous anthology. Taken from the short works of Hawthorne, Poe, Melville, London, Bierce, Washington Irving and others, it is buttressed as a piece of scholarship by Dr. Franklin's introductory essays. He sees science fiction as an evaluation of technology and an attempt to relate it to the remainder of human existence. Some scholars speak of a broader SF, containing a narrower science fiction among other sub-genres, and some of them might apportion some of Franklin's selections to those other segments of the spectrum. But this is a highly respected study, and obviously a viable one.

Suppose an alien spaceship set down in medieval England and carelessly left its landing ramp lowered. Suppose a sucessful charge up that ramp by mounted knights outraged by the demons and dragons inhabiting this mobile keep. What then? Spacefaring crusaders? Interstellar settlements by stouthearted peasant folk and their liege lords, innocent of internal combustion but operators of an awesome starfaring device? Why not? Why not, indeed, and for a lusty, brawling, and in the end magnificent account, see Poul Anderson's The High Crusade .

The Sword of Shannara , now being issued in standard news rack size, spent much of 1977 setting sales records in various other formats. The present edition retains the lush Hildebrandt illustrations, which add a nice decorative touch to this tale of elves and trolls, dwarves, the evil Skull-Beavers, and the ultimate struggle the magical sword.