Virtually without special effects, stage sets or make-up, Don Siegel created one of the most terrifying science fiction films of all time. The setting is all-too-recognizable-a small town in California-and so are the monsters: Mom, Dad, and little Timmy. Or rather, their clones, hatched from giant pods to whom they show an affectionless allegiance. It is an allegory of totalitarianism, not specifically governmental (although references to the McCarthy Committee as well as to communism were inevitable), but rather cultural: the totalitarianism of blind conformity. "I think that the world is populated by pods and I wanted to show them," Siegel has said. "I think so many people have no feeling about cultural things, no feeling of pain, of sorrow..." The film derives its enormous energy and relevance from Siegel's all-American, low-budget expressionism: shooting everyday locations from a low- and wide-angle perspective, he alien-ated the normal. So buildings threaten to eat up Main Street, and a pitchfork shoots out from a greenhouse with almost 3-D terror. In the end, Invasion of the Body Snatchers contributes the most effective kind of horror there is for modern times, the horror of ambiguity: are those alien clouds over California or are they just clouds? And if that's my wife, why don't I know her?