The life of J.M. Barrie (1860-1937) would make a fascinating film. Sadly, Finding Neverland, which stars Johnny Depp as the Scottish playwright and novelist, isn't it.

Because Barrie's best-known work, "Peter Pan," turns 100 later this year, it's easy to understand why director Marc Forster was drawn to its author11just as it's easy to imagine, given the unremitting bleakness of his last film, Monster's Ball, why he may have longed for Neverland himself. But while Forster and screenwriter David Magee (working from a play by Allan Knee) aspire to Barrie's sense of wonder, they're all too willing to settle for sentimentality.

Even more lamentable, they create a fairy tale version of a clever but deeply conflicted man who did not, for the most part, lead a happily-ever-after life. When Barrie wanted a happy ending, he had to write one.

By the time the curtain of London's Duke of York Theatre rose on Dec. 27, 1904 and introduced the world to "the boy who would not grow up," Barrie was already one of Britain's best-loved writers. The author of such noted works as "Quality Street" and "The Admirable Crichton," he enjoyed acclaim on both sides of the Atlantic and numbered Thomas Hardy and other literary figures among his friends. Following the tremendous success of "Peter Pan," he was named a baronet by order of the British crown.

But as writer Andrew Birkin shows in his often heartbreaking biography, "J.M. Barrie & the Lost Boys: The Love Story That Gave Birth to Peter Pan," James Matthew Barrie was himself the original lost boy. The death, when Barrie was just 6, of a revered older brother and his mother's incapacitating grief apparently left him stranded between childhood and adulthood, as did his own slight stature--as an adult, he stood just five-foot-three. Yet Barrie also worshipped children: their sense of imagination and adventure, not to mention their irreverence (he was thrilled, Birkin notes, when his godson told him his favorite part of "Peter Pan" "was tearing up the programme and dropping the bits on people's heads.")

Although he married one of his leading ladies, Mary Ansell, in 1894, theirs was an unhappy (and most likely sexless) union, and Barrie formed his deepest emotional attachments with young children and their mothers, none more so than the five Llewelyn Davies boys--George, Jack, Peter, Michael and Nico--and their by-all-accounts enchanting mother, Sylvia.

For Barrie, who first glimpsed the older boys playing in Kensington Park in 1897, it was pretty much love at first sight. Slowly but surely, and to the quite understandable irritation of the boys' father, barrister Arthur Llewelyn Davies, he began inserting himself into their family life, inventing elaborate entertainments for the boys and weaving them into his own stories, one of which eventually became "Peter Pan." Following Arthur's untimely death in 1907, it was Barrie who supported the family; when Sylvia died just three years later, it was Barrie who became their legal guardian.

What Barrie felt for the five boys, most especially George and Michael (both of whom died as young men), seems a dense tangle of tender solicitude and tightly suppressed eroticism. To contemporary ears, Barrie's fervid letters and journal entries, as quoted by Birkin, can sound uncomfortably close to pedophilia. Yet Nico, the youngest brother, flatly denied all such allegations, calling Barrie "an innocent; which is why he could write 'Peter Pan.'" The assessment of the brother who lent his name to the play (and who grew to hate the association) was considerably darker: "(In) the end," Peter Llewelyn Davies wrote, "his connection with our family brought so much more sorrow than happiness."

That someone could be utterly devoted and still do damage is not, however, the story that Finding Neverland chooses to tell. By setting the film's opening scene at the theater, Forster and Magee acknowledge with a wink (and with a disclaimer reading "inspired by true events") that they are making a work of fiction. Yet every change they make--killing off Arthur Llewelyn Davies before Barrie meets the family; making Mary Barrie largely responsible for the failure of their marriage; turning Sylvia's mother into a prototype for Captain Hook--is done to skew the movie in Barrie's favor and to absolve him of his more questionable motives. This is a shame, because Forster has the kind of dream cast--not only Depp, but also a pair of glorious actresses, Kate Winslet as Sylvia and Julie Christie as her mother--who could have gone far deeper and darker if only they'd been asked.

Finding Neverland's central premise--that our imaginations are our best defense against both life and death--finds its fulfillment not in the film itself (whose fantasy sequences are too literal), but rather in the glimpses it allows of Barrie's play, which is staged with both charm and genuine pathos. As an elderly theatergoer tells Barrie after opening night, "It's all the work of that ticking crocodile. Time is after us all." In moments like these, Forster succeeds in finding Neverland. It's a shame he lost sight of the man who created it.