The Nickelodeon film, however, consists chiefly of Harriet M. Welsh (the very cute Michelle Trachtenberg) and her adventures with other people. That's understandable: moviemakers don't like solitude. They much prefer for their characters to interact with other specimens of humanity -- never mind that most life lessons and coming-of-age wisdom come from reflection and introspection. People look better on-screen when they're talking to someone else.

I forgot that. I forgot, foolishly, how Disney changed Beauty and the Beast from a story about a resolute young woman to brightly colored pap about a girl and her singing teapot pal. Silly me: I expected Harriet the Spy to be told in voice-over. I thought we'd get the story from Harriet and her notebooks.

But Harriet's notebooks get short shrift: the longest scene of Harriet and her beloved writings shows a contrite Harriet, brooding in her room after her notebooks have been read by others. Only the setup scenes spend any time with our spy and her spy kit.

The rest of the movie is about her friends: first she's with them, then on the outs with them and then back with them again. Luckily, her friends, Janie Gibbs (Vanessa Lee Chester) and Sport (Gregory Smith), are entertaining. Janie aspires to a career in science and performs many ooky experiments in her bedroom. Sport is the man of the house, cooking and cleaning for his starving-artist dad. (Sport is extra special because Gregory Smith can really act, like, with subtlety and everything. It seems as though every film released this summer depends on one character actor, one minor role played with a spark. In Harriet the Spy, that role clearly belongs to Smith.)

Harriet the Spy is the first feature released by Nickelodeon Movies, and yes, it looks like TV. Smith, Chester and Trachtenberg have all acted before on television; Smith and Trachtenberg have even appeared on Nickelodeon shows. Harriet was written by television writers -- Clarissa Explains It All headwriter Douglas Petrie and NYPD Blue writer Theresa Rebeck -- and, naturally, they reproduce on the screen the rhythms of broadcasting. Instead of separating the scenes with commercials, Harriet separates scenes with annoying montages that look like commercials. Some of the montages are interesting -- when Ole Golly (Rosie O'Donnell) and her suitor take Harriet to see Mata Hari, the montage features Greta Garbo and leading men on the silver screen and Golly and her man in the silver-lit theater. Cute or no, there's too much of this rapid-fire images-to-music stuff.

Unlike the book, the movie consists chiefly of upbeat parts. In fact, the only genuinely poignant moment comes when Harriet, told she smells, tries to bathe in the little girls' room sink, in case she really does stink.

The nanny, Harriet's significant adult, is also happified for the big screen. Ole Golly (pronounced "gully" in the movie) mysteriously wears a claret-colored coat and hat most of the time (perhaps she's supposed to be similar to Julie Andrew's Mary Poppins); she's not at all similar to the book's Golly, a proper nanny. O'Donnell's Golly is a buddy nanny; this is probably because, in movies, all relationships must be buddy, romantic or adversarial. Just as the moviemakers can't leave Harriet alone with her thoughts, they can't have her respecting and feeling secure with someone who isn't warm and cuddly. In the context of the movie, O'Donnell's Golly is okay -- but why did the filmmakers feel the need to make Golly, as director Bronwen Hughs says, "a lot cooler than readers remember"?

I think they made that choice for the same reason they made Harriet part of a gang, rather than a loner: because the movie Harriet the Spy is more about the conventions of the movies than it is about the spirit of the book. The movie's okay if you're a sixth-grader -- it's not bad, the heroine is tough and the cineplex holds nothing else for you. But even so, you'd be better off reading the book.

-- Edith Sorenson

Harriet the Spy.
Directed by Bronwen Hughes. Starring Michelle Trachtenberg and Rosie O'Donnell.

Rated PG.
97 minutes.