Saoirse Ronan's new film Little Women hasn't been released yet and she's already she's winning the best reviews of her career.

From her breakthrough role in "Atonement" to the indie hit "Lady Bird," to the about-to-be-classic "Little Women," Saoirse Ronan, 25, has proved she has the talent and range to tackle any role she has a mind to.

"Little Women" (opening December 25) looks ravishing. It's beautifully shot, it features a quartet of charismatic young actresses as the March sisters, it features an ideally cast young male lead in Timothee Chalamet and every detail from the costume design to the locations are superb.

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Eliza Scanlen, Saoirse Ronan and Emma Watson in Little Women

Eliza Scanlen, Saoirse Ronan and Emma Watson in Little Women

But Ronan and Gerwig have something more ambitious in mind than a gauzy portrait of four girls facing the many ups and downs of romance and the real world. 

Their version of "Little Women" remains true to its source material but it includes the real-world struggles of writer Louisa May Alcott, the woman who wrote the classic 1868 novel. 

When we first see Jo March she is running. In this case to the offices of the New York scandal sheet that prints her not exactly literary short stories, the success of which helps to keep a roof over her families head. 

From our first glimpse of Jo, we know a few things about her. She's self-possessed, determined, watchful and no one's fool. In her exchanges with the editor and publisher who prints her work she consistently holds her own, which by the standards of 1868 (the time that "Little Women" was first published) are remarkable.

Saoirse Ronan as Jo March and Timothee Chalamet as Laurie in Little Women

Saoirse Ronan as Jo March and Timothee Chalamet as Laurie in Little Women

What follows is as unexpected as it is pure, Ronan and Gerwig's film adaptation is the most perfectly realized period drama since "A Room With A View" but it's also a bit of a feminist hand grenade, calculated to inspire a new generation of smart, spirited girls (and boys) to strive to be their best selves and not to let other people's prejudices or sexism get in their way.

Just like Alcott did in 1868, Gerwig and Ronan bring great realism and depth to their portrayal of the March sisters, making us root for them before we even notice.

Jo (Ronan) is the headstrong one and the most obvious stand-in for Alcott herself, Meg (Emma Watson) is the oldest sister who's as kind as she is upright, Beth (Florence Pugh) is the quietest one and the most artistically gifted and Amy (Eliza Scanlen) is the youngest and most passionate of the crew, given to huge tantrums that infuriate all around her. 

They're as recognizable as the people you grew up around in other words, which is why the book still has so many fans over 150 years since it was written. The all-star cast includes Meryl Streep as Aunt March, the crotchety old bat whose withering barbs almost hide the fact that she has the four girls' best interests at heart.

Emma Watson, Saoirse Ronan, Eliza Scanlen and Florence Pugh in Little Women

Emma Watson, Saoirse Ronan, Eliza Scanlen and Florence Pugh in Little Women

Streep plays Aunt March as a snob who understands the world of men and who frets that the March girls are too romantic or too silly to contend with what real life will throw at them.

Streep's portrayal is our first tip-off that this is going to be more than a simple tale about four girls who may marry well. You can see real anxiety in her conversations with each of her nieces that they take their heads out of the clouds before they lose their shot.

Being a woman of her age that means Aunt March thinks the solution is to marry a rich young man. She can not see the paths to a truly independent future that Jo or Meg sees. 

Timothee Chalamet as the lazy, rich neighbor Laurie is ideally cast. You can see that his future could go either way, perhaps he'll stay true to the good nature he was born with, or perhaps his elevated position and influence will corrupt him and turn him into another one of the good for nothing men he can see all around him.

Saoirse Ronan as Jo March and Timothee Chalamet as Laurie in Little Women

Saoirse Ronan as Jo March and Timothee Chalamet as Laurie in Little Women

Money, getting it, losing it, seeking it, ignoring it, looms so large over the March sisters' futures that it's practically a character in itself. The March girls come within a whisper of destitution, then they come close to a rich marriage that will change their fortunes, but in the end by remaining consistent with their own values they win the biggest prize of all, their own self-respect.

This "Little Women" is that rare thing, a perfect film because it's stuffed with so many flawless performances that you'll have a job to decide which one you liked the most. It's also on its way to being the defining classic, the last word on Alcott's text. 

But even at the end Ronan and Gerwig have some surprises in store. It would betray the text and the writer to simply marry off the March girls and fade to black. Instead, they show us Jo stepping into herself as a young woman and a successful writer and teacher, all on her own terms and in her own time.

That image alone will inspire a generation. 

Little Women opens December 25.