Sci-Fi's Top 100: 1-50

18 E.T.: The Extra-Terrestrial (1982)

There's a reason why this is one of the most popular films of all time. Director Steven Spielberg's gentle fairy tale about a 10-year-old (Henry Thomas) who adopts a stranded alien is irresist-ibly uncynical, a heartfelt visual poem about the power of friendship. ''E.T.,'' Spielberg has said, ''is the closest film to my own sensibilities, my own fantasies, my own heart.'' It shows.

19 Amazing Stories (1926-94)

Publisher Hugo Gernsback (for whom the Hugo Awards were named) launched the first English-language periodical devoted to ''scientifiction.'' Reprinted tales by Jules Verne, H.G. Wells, and Edgar Rice Burroughs rubbed shoulders with those by newcomers such as Jack Williamson. Early readers who joined its stable of writers included Arthur C. Clarke, Isaac Asimov, and Robert A. Heinlein. Despite occasional regressions to hackneyed formulas, the magazine was the first to give the genre form, definition, and respect.

20 A Trip to The Moon (1902)

Thomas Edison and the Lumiere brothers may have invented movies, but it was French stage illusionist George Melies who became the father of special effects. With tricks both theatrical and cinematic, the goofy, endearing Le Voyage dans la Lune retains a sense of wonder that runs straight to ILM. Imagine seeing it in 1902: Suddenly, anything must have seemed possible.

21 I, Robot (1950)

Isaac Asimov fans may argue that his Foundation trilogy is as important, but it's this group of short stories that makes our cut, mostly for defining the robot prototype. In short: A robot ''may not injure a human being,'' ''must obey the orders given it,'' and ''must protect its own existence as long as such protection does not conflict with the First or Second Laws.'' Of course, robots have been obeying and breaking these laws ever since.

22 A Clockwork Orange (1971)

Lashing us with a bit of the old ultra-manipulation, Clockworktests our morality by posing a sex- and violence-obsessed Alex (Malcolm McDowell) against a physiologically leashed Alex. With blaring design, a Moog-synthesized classical score (was Beethoven's Ninth ever the same afterward?), and grimace-inducing scenes of rape and pillage, director Stanley Kubrick, working from Anthony Burgess' 1962 novel, sears a frightening image of an all-too recognizable future into our brains.

23 The Terminator/Terminator 2: Judgment Day (1984, 1991)

In his first great film, director James Cameron took Arnold Schwarzenegger, a meager $6.5 million budget, and a patchwork of classic science-fiction references to fashion an archetypal modern nightmare: the unstoppable killing machine. Seven years later, Cameron returned to his creation and added state-of-the-art F/X and a pumped-up Linda Hamilton to create a visceral, eye-popping thrill ride. In both cases, we were floored by the intensity of the visions.