WHEN I FIRST started teaching science fiction, colleagues would look at me oddly and say "Sci-fi? Oh, you mean flying saucers and that stuff?" Now they look at me oddly and say "Science fiction? Well, my 10-year-old liked the Star Trek movie . . ."

Thanks to Star Wars, Star Trek; The Motion Picture and The Black Hole, most North Americans think they know what "science fiction" is. What they're seeing, though, is a visual version of 1930s pulp magazine sf: lots of action and hardware, little concern with technique or character development. What they're reading, if movie tie-ins and hype convince them to try some paperback sf, is equally out of date.

Star Trek: The Motion Picure (Pocket Book, $2.50, paperback) is a case in point. The novelization, credited to Star Trek's creator Gene Roddenberry, "based on the screenplay by Harold Livingston and the story by Alan Dean Foster," gives the basic plot of the movie. But so what? If you haven't seen the movie, you'll ruin any suspense the producers may have created. (The biggest question, for me, was "How are they going to get Spock back on the Enterprise?") If you have seen it, the book offers a bit more character development, but the flat prose (which strains for ultraviolet italics in the final "transcendent" sequences) can't hint at the special effects that wow the audiences. The minimally competent writing, flat characters and emphasis on action are all reminiscent of pulp sf, as is the plot: All-American rugged individualist Hero and faithful crew save the world from the Awesome Menace by the power of Human Understanding and Love. (I admit that 1930s sf wouldn't have contained a footnote explaining why Kirk and Spock aren't lovers, or the comment that Kirk, regaining control of the Enterprise, "had that look which comes into some men's eyes when they've just won a woman and she lies there ready to be taken.")

By the 1950s in North America, new sf markets -- hardcover books, and magazines like Galaxy and The Magazine of Fantasy and Science Fiction -- were presenting a new type of sf. Writers were increasingly concerned with style, character development and social satire, as Martin Harry Greenberg and Joseph Olander remind us in their introduction to Science Fiction of the Fifties (Avon, $4.95, paperback). The 21 stories range from the sentimentality of Theodore Sturgeon's "Saucer of Loneliness" (misfits, probably including sf readers, really are superior people) to the stylistic brilliance of Alfred Bester's "5,271,009" (a psychological study of wish-fulfillment, with a most unusual devil). The main focus, though, is acid social satire (for example, Frederick Pohl's "Happy Birthday, Dear Jesus," which carries the commercialization of Christmas to logical extremes) and thoughtful social comment (for example, Damon Knight's study of a too-tranquil Utopia in "The Country of the Kind").

The list of contributors reads like a who's who in science fiction of the last three decades. The stories, commentary (by the editors, with assists from Frederick Pohl and Barry Maltzberg) and selected bibliography are an excellent introduction to modern sf. The companion volumes for the 1930s and 1940s are equally good.

Contemporary Soviet sf (or at least the selection which reaches us) bears a distinct resemblance to much of this '50s material. I read New Soviet Science Fiction (Macmillan, $10.95) with a strong sense of deja vu. The 14 stories (by 8 writers and once co-author team) present, for the most part, earnest moral fables like "The Violet" by Ilya Varshavsky (a fragile flower is more beautiful than the wonders of a plastic global city), and clever satires, usually aimed at bureaucracy, a favorite Soviet target. The styles range from '30s-ponderous, with creaking explanation (apparently regarded as a mark of serious literary and intellectual intent in Eastern European fiction) to 1950s smooth. Helen Saltz Jacobson, who translated the first dozen stories, has done a competent job. The collection is interesting for a fan of traditional sf, and for anyone who wonders about the differences between East and West, between human beings. No women authors, however, are represented, and there are few major women characters -- a situation which was changing in North America in the '50s.

The real surprises of the collection, for me, were the last two stories, "The Friar of Chikola" and "A Provincial's Wings" by Vadim Shefner. Both are brilliantly translated by Alice Stone Nakhimovsky and Alexander Nakhimovsky, who made me forget I was reading a translation. The first is a whimsical tale of a man's obsession with breeding four-legged chickens. The second is a lyrical sensitive account (with folk-tale overtones) of a rural postman's everyday life and his attempts to invent useable wings. Shefner's work points to a potential of contemporary sf, in any country, to combine literary sophistication and psychological depth with that extra kick of new ideas, to produce a unique (and for us fans, addictive) sense of wonder.

No editor is credited with assembling this collection. Editorial material, including information on the authors, dates of original publication and suggestions for further readings, is sorely lacking.

Currently, the Eastern European writers who best satisfy North American tastes in "literary" sf are Poland's Stanislaw Lem and the USSR's Arkady are Boris Strugatsky. Lem's Tales of Pirx the Pilot (Harcourt Brace Jovanovich, $8.95) is a comparatively lightweight, humorous account of the misadventures of a bumbling space cadet. I found the colloquial translation by Louis Iribarne rather jarring but the five tales are entertaining.

Far Rainbow/The Second Invasion from Mars (Macmillan, $9.95) presents the Srrugatskys, and sf, at the height of their form. The first story, transltated by Antonina W. Bouis, is for me one of the best novellas to appear in English in 1979.

The material is familiar. An idyllic planet, Rainbow, is destroyed by indiscriminate experiments tampering with its ecology, and by bureaucratic bungling. The story is distinguished by an effective style, which creates suspense by jump-cutting between scenes; and by a focus on the convincing human reactions to the disaster.

"Second Invasion" illustrates the Strugatskys' gifts for mordant social satire. The unheroic narrator, Phoebus Apollo (who just wants to be left alone with his stamp collection) tells us how he helped to stamp out dissidents, and welcome the Martians, who want, not conquest, but unlimited supplies of human stomach juice.

As for the best of Western science fiction -- check this column next month, when Joanna Russ will review award-winner Vonda N. McIntyre's collection, Fireflood and Other Stories (Houghton Mifflin, $10.95).