Half a century ago, a middle-aged newspaperman with a few obscure books to his name sat down to pursue a pet obsession based on a story that had never sold.

The ensuing 1965 novel -- in which his agent had no confidence -- sagged at first. But within a few years, it was a pop-culture sensation, and this year, on its 45th anniversary, "Dune" is one of science fiction's best-known books and probably the field's bestselling novel.

The mystery of why some works continue to speak to us is heightened with a book like "Dune": Frank Herbert's desert-planet epic not only remains popular and well-known, but this tale has anticipated many of our contemporary concerns. Its saga of dueling great houses, the fight for a rare resource and a young aristocrat's coming of age was set 200 centuries in the future. But it grapples with numerous issues pressing in the 21st: the fragility of the environment, the shortage of fossil fuels, the threat of religious jihad, the unpredictable effects of mind-bending drugs.

"It was the SF book that everybody in the mainstream culture was reading," recalls Northern California novelist Kim Stanley Robinson. "But it wasn't like Vonnegut's 'Cat's Cradle,' which was essentially a mainstream novel. Herbert was doing hard-core SF in the anthropological and world-building sense. People went for its huge back story taking off from [the prophet] Mohammed's life."

That the novel was planned and researched during the Eisenhower and Camelot years -- before widespread Muslim fundamentalism, OPEC, mainstream narcotics use and other issues that seem to inspire the narrative -- underscores the author's prescience. The book also helped galvanize the environmental movement: Set on a world far from ours, its rich description of a water-poor planet is credited by some as the inspiration for Earth Day.

Because of its huge following, fast-moving plot and opportunities for special effects, "Dune" has repeatedly attracted other artists -- it's been the source of a video game, a board game, numerous posthumous sequels and several adaptations. And though a 1984 film was widely considered a failure and two subsequent Sci-Fi Channel miniseries were made, Paramount recently selected a director for a big-budget movie.

The inspiration

"I am a political animal," Herbert said in a 1983 promotional interview. "And I never really left journalism. I am writing about the current scene -- the metaphors are there."

The novel was sparked when, in the late 1950s, Herbert flew to Florence, Ore., in a small chartered plane to write about a U.S. Department of Agriculture effort to stabilize sand dunes with European beach grasses. The author was struck by the way dunes could move, over time, like living things -- swallowing rivers, clogging lakes, burying forests. "These waves can be every bit as devastating as a tidal wave . . . they've even caused deaths," he wrote his agent, beginning an article, "They Stopped the Moving Sands," that was never published.

Despite his agent's indifference, Herbert dug in: He was fascinated by the project and superimposed the history of another sandy place -- including Arabs and Islam's Mohammed -- into an adventure novel originally called "Spice Planet."

When he hit his stride, Herbert was writing 70 pages a week.

At the time, science fiction was at the tail end of its Golden Age, dominated by brisk tales of interstellar war and planet hopping. Several icons of midcentury were doing major work -- Robert Heinlein, for instance, published his campus sensation "Stranger in a Strange Land" in 1961 -- but the field's energy was flagging, and the magazine market had imploded. (A 1961 fanzine was titled "Who Killed Science Fiction?") Herbert and his gargantuan manuscript were turned down by dozens of publishers but eventually accepted by Chilton, a small press known for auto manuals.

Herbert's story of young aristocrat Paul Atreides, along with maps, appendixes, glossary and epigrams ran to more than 500 pages. After almost two years, the book took off in 1967. The novel was a hinge between new and old, says Annalee Newitz, editor of science fiction blog io9.

" 'Dune' functions nicely as a transition between classic SF -- focused on space opera and astro-politics of the kind Isaac Asimov and other golden age authors wrote -- and the next generation," she says. "In the '60s, we saw a shift away from science fiction focused on space travel and space politics to anthropology. You aren't rushing between planets, you've landed on one and you talk about that one" -- including its biology and sociology.

Writers had imagined life on other planets and written of environmental catastrophe. But the scale of "Dune" was unprecedented, comparable, as Arthur C. Clarke said at the time, only to "The Lord of the Rings."

"The planet was something you could really feel," says Robinson, whose latest novel is "Galileo's Dream." "Herbert spent a lot of time outdoors -- you can see it in the writing, he's seen things you can only see if you've been there. It's physical and expansive."

Still, the novel's pulp roots show.

"Parts of it are almost poetic," says Rob Latham, who teaches science fiction at UC Riverside. "But the villains are comically ridiculous. Baron Harkonnen could have been played by Sydney Greenstreet or Charles Laughton, say -- 'swishy.' And I don't know what we're supposed to think of the eugenics. There are all sorts of half-baked ideas in there."

'A real mess'