Author! Author! 

It’s easy to fail when making a film about a writer, because it’s difficult to compellingly film somebody writing. Painting, sculpting, boxing and wicker crafts all lend themselves to visuals. Writing is just a woman at a desk or a typewriter, pouring her life onto a page.

Writers are more interesting before or after they’ve written, and that’s what we see in Iris, the new film based on John Bayley’s memoirs of his life with Iris Murdoch, one of the more popularly obscure English novelists of the past century. Murdoch wrote more than two dozen well-loved novels delicately based on philosophical concepts and a series of recurring themes, winning the Booker Prize and earning an unimpeachable scholarly reputation.

But her novels aren’t cinematic (only one has been filmed, in 1971), and she didn’t write them naked, or on the back of a speeding car, or while there was political upheaval around her. Instead, the film argues, Murdoch lived aggressively and fully—something that’s always fun to film, particularly when it can be turned into an acting showcase for two of England’s best female actors.

The film, co-written and directed by Richard Eyre, focuses on Bayley’s initial meetings with Murdoch in their youth, intercut with stories of their old age, when Murdoch was stricken with Alzheimer’s disease. We don’t see a great deal of writing. Instead, we see two starkly different slopes to a towering life.

The young Iris is played by Kate Winslet, with a distinctive haircut and a large dose of the wide-eyed sexual curiosity she’s brought to nearly every one of her films since Heavenly Creatures. The aging Murdoch is played by Judi Dench, who bears a startling resemblance to the writer. Both performers charge into their roles with no inhibitions or even many conceits, carrying a sometimes meandering, precious film on the strength of two fascinating, original portraits.

Winslet revels in her performance as a woman who seems to have messed around with nearly every man and woman at Oxford in the mid-1950s. Meanwhile, Dench spends much of her time in Murdoch’s descent into her disease. One performance sets up the other, with Winslet’s vibrancy underscoring Dench’s eventual helplessness.

Dench and Jim Broadbent, playing Bayley, do astonishing work as a couple cast into dire circumstances. Murdoch’s illness puts both principals in horrifically unfamiliar surroundings as a smart, clever woman becomes exceedingly vacant while her husband watches. Dench and Broadbent are heartbreakingly convincing as two old people who never planned on the troubles of getting old together.

It’s somehow fitting that a film about such a glamourless topic is turned into such a vibrant showcase for actors. All three Oscar-nominated leads (and even Hugh Bonneville as the young John) work their tails off to maintain a compelling tone to this endeavor, and they succeed splendidly. The film hops back and forth between Winslet and Dench with enviable agility, since the actresses show a remarkable facility for embracing each other’s work. Winslet seems the more adaptable of the two, as she should be; her Iris contains less of herself and more of Dench’s regal mannerisms and depthless pleasantness. Both actresses make this less-than-cinematic novelist into someone eminently worth filming.

In the end, Iris isn’t a film about writing. It’s about acting—the best kind of acting, the revelatory interpretations of existence from actresses who care about their craft. Specifically, it’s about the fine work done by every main character in a film that sometimes loses relevance simply from its decidedly interior subject matter. There isn’t a message or a moral here, per se. Iris is a look inside the beginning and ending of a life, with all the incompleteness and sadness that implies.