With "War of the Worlds," Steven Spielberg returns to the scary territory of "Jaws" and "Jurassic Park" and once again proves himself to be the most gifted movie entertainer of his generation.

The film, which transplants H.G. Wells' 1898 novel about an alien invasion to the present day, contains all of the hallmarks of classic genre Spielberg: It shows you things you've never seen before, instills an accompanying sense of awestruck wonder, and delivers long stretches of heightened, delirious excitement that remind you why people started going to the movies in the first place.

This is the kind of thing Spielberg has been doing throughout his career, long enough for us to take him for granted (and become intolerant when his movies are only partly successful, as with "A.I. Artificial Intelligence" or "Empire of the Sun"). But when Spielberg is "on" - when his heart is in it and the material is strong enough to support his ambitions - his films exceed our expectations and stoke our general love of movies a few degrees hotter. Spielberg makes us care about the medium because, unlike many of his peers, he taps into the purity, depth and energizing rush with which films can affect us.

"War of the Worlds" ranks among the best of Spielberg's crowd-pleasing entertainments, but it also stands alongside the more serious "Schindler's List" and "Saving Private Ryan" because of its surprisingly grave tone. It is a movie about doomsday from the skies set in a post-9/11 America, where such a scenario is no longer relegated strictly to the science-fiction realm. The script, by Josh Friendman and David Koepp, relates the story entirely through the eyes of Ray Ferrier (Tom Cruise), a divorced New Jersey dockworker, and his two children, 11-year-old Rachel (Dakota Fanning) and the surly adolescent Robbie (Justin Chatwin), who are spending the weekend with their estranged dad.

In a series of quick scenes, Spielberg deftly sketches the quotidian messiness of Ray's working-class, single-guy life and the tension between him and his kids, who resent him for being such an uninvolved parent and seem to tolerate him more than anything else.

That all changes, of course, once the aliens arrive, bringing the end of the world with them. Instead of using a broad, spectacular canvas a la "Independence Day," Spielberg personalizes the apocalypse in "War of the Worlds": The scariest moments come when the family unit is placed in peril, be it when a panicked mob threatens to separate Rachel from her father, or a scene in which a desperate Ray must decide which of his two kids to attend to first, a la "Sophie's Choice" (the theme of family, the most recurring in Spielberg's works, also dominates the film's purposely low-key climax, which is destined to be criticized but is faithful to Wells' book).

Spielberg takes a sober approach to the movie's big "wow" moments, too. The first appearance of the aliens has the documentary realism of the Omaha Beach sequence in "Saving Private Ryan" (cinematographer Janusz Kaminski shot both films), with crowds of terrified people running down the street as the aliens' death ray picks them off at random, vaporizing them into a cloud of dust. "War of the Worlds" makes you feel the sting of every human death, an approach that's practically unheard of in the disaster-flick genre, where the enjoyment comes from the vicarious thrill of watching mass destruction from the safety of your chair.

All of this is not to say that the movie isn't outrageously, fantastically fun. Spielberg is obviously out to play in "War of the Worlds": You can see it in the astonishingly long tracking shot that circles the Ferriers' minivan - and even weaves in and out of the vehicle - as Ray drives along a highway clogged with people fleeing a disaster zone.There is also a seven-minute, nearly silent setpiece in which the family is hiding inside a basement, trying to elude detection by the aliens, that is a mini-masterpiece of sustained suspense for its own sake - a clear elaboration on the velociraptor kitchen attack from "Jurassic Park," only much more imaginatively mounted and shot.In that scene, you can feel Spielberg trying to top himself, to push himself creatively for the benefit of the audience. The fact that he succeeds so formidably suggests that at 58, Spielberg is still learning, still excited by the possibilities of movies. The director is currently filming a still-untitled drama about the 1972 Munich Olympics, which is due in theaters at Christmastime.It's the same feat he pulled off in 1993, when "Jurassic Park" and "Schindler's List" were released six months apart. One was a commercial entertainment, the other a serious work of art, and it was the latter that understandably (and rightly) received the most acclaim. But "War of the Worlds," despite its genre roots, is also art of the highest order. It just happens to go great with popcorn.