It's almost axiomatic to say that Pixar movies are just as enjoyable for adults as they are for kids. But in the case of Pixar's most recent hit, " Up," out on Blu-ray and DVD this week (Disney, $39.99 2-disc DVD, $45.99 4-disc Blu-ray combo, rated PG), the path-breaking animation studio may have made a film that's even more pleasurable, and meaningful, for grown-ups than for children.

To be sure, "Up," like its Oscar-winning predecessors from Pixar ("WALL-E," "Ratatouille," "The Incredibles" and "Finding Nemo"), has been a hit for all ages. Released at the end of May, "Up" is the third-highest-grossing film of the year so far, according to Box Office Mojo, taking in nearly $300,000 at American movie theaters. And one of its protagonists is an 8-year-old Wilderness Explorer named Russell (voiced by Jordan Nagai).

Yet Russell turns out to be a secondary character in "Up," a youthful force who helps set in motion the real star of the film, a crotchety 78-year old balloon salesman named Carl Fredricksen (voiced by Ed Asner and drawn to resemble an old Spencer Tracy).

The movie, directed by Peter Docter and written by Docter and Bob Peterson (also credited as the co-director), is actually about the life and unfulfilled dreams of Carl, who we first meet as a kid in the 1930s. Young Carl is entranced by the exploits of adventurer-explorer Charles Muntz (voiced by Christopher Plummer), who flies a dirigible and is famous for, among other things, his search for a rare, giant bird in Paradise Falls, located somewhere in South America. It's Carl's adventurous spirit that binds him to an even more daring girl his age named Ellie.

In a surprisingly moving five-minute silent montage, set only to music, we witness the family history of Carl and Ellie, from their first meeting to their falling in love to marriage to rebuilding a dilapidated house to old age. This memorable sequence, called "Married Life" by the filmmakers, shows the deep, lifelong love between Carl and Ellie, and their deferral of planned adventures as real-life problems intrude.

But it also reveals, in a rarity for a film apparently aimed at children, the tragedies of their life together, in particular Ellie's miscarriage, and the emptiness and despair Carl feels when Ellie dies.

Carl attempts to fulfill a dream he and Ellie had always shared — to take a trip to Paradise Falls in search of the long-lost Charles Muntz. The means of Carl's travel is extraordinary — in one of the most beautiful sequences in Pixar films, he ties thousands of colorful helium-filled balloons to his house, and he flies away in it. But there's one big snag. Carl has a stowaway in his flying house — the not particularly resourceful Russell.

Carl and Russell's adventures when they reach Paradise Falls won't be detailed here, except that they encounter Muntz, still alive, but mean and cunning, and his obedient pack of dogs, all of whom are equipped with special collars that allow their thoughts to be heard. The friendliest of the bowsers is Dug, who cares about nothing but pleasing humans ("I have just met you and I love you," says the tail-wagging, tongue-licking golden retriever) —except when a squirrel races by or a ball is thrown.

Making a senior citizen the star of "Up" is a departure for Pixar, and the film includes some clever humor about hearing aids, canes and handicapped-parking spaces. The creation of Carl is explored by Docter and Peterson in their affable and informative audio commentary on all versions of the film. Interestingly, Docter says that he was initially worried about the silent "Married Life" sequence, but that when it was shown to his colleagues in storybook format (included here) "people were moved to tears." In "Geriatric Hero," a short documentary available only on the Blu-ray edition, we learn how Pixar animators went to retirement homes to do research on how seniors move and talk.

My guess is that adult dog lovers will appreciate even more than children the jokes and subtleties Pixar delivers about the dogs in "Up."