Iris Murdoch's brilliant, convoluted, frenetically funny books made her into one of the most celebrated English novelists of the 20th century, but most readers remained in the dark about the end of her life until a few years ago. That's when her husband, the distinguished literary critic John Bayley, came out with volumes of memoirs of his life with her and the way he -- a stuttering, klutzy, bespectacled, balding, virginal young literature professor at Oxford -- fell for the self-assured, sexually adventurous university fellow and tutor. His books also detailed how the onset of Alzheimer's disease eventually destroyed Iris' great mind and turned John into her caretaker.

Iris is the film version of this story, with Hugh Bonneville and Kate Winslet playing the younger version of the couple, and Jim Broadbent and Judi Dench as the older John and Iris. The actors are far and away the best part of the movie. Winslet brings her usual luminescence to young Iris, and Dench gives a technically fine performance as the older Iris (though the role forces her to play the disease more than the character, so it's less rewarding than most of her other recent roles).

This show, however, belongs completely to Jim Broadbent. With his paunchy physique, balding head, and weak chin, he's often picked to play genial, harmless middle-aged-to-old guys, most recently as Bridget's dad in Bridget Jones's Diary. More creative directors have put facial hair on him and cast him more interestingly -- as a folksy bartender in Neil Jordan's The Crying Game, a stage actor with a compulsive eating problem in Woody Allen's Bullets Over Broadway, the gruff, emotionally closed-off W.S. Gilbert in Mike Leigh's Topsy-Turvy, and a flamboyant, Madonna-singing showman in Baz Luhrmann's Moulin Rouge. (Even without facial hair, he still made an oily Duke of Buckingham to Ian McKellen's Richard III.) This film has him back in his genial, harmless mode, yet he does amazing things with a role that escapes being a total cliché only because it's given to a male actor -- Jennifer Connelly played the same kind of role in A Beautiful Mind. His grief is palpable, and in one scene, so is his rage at her condition when he screams at her while they're lying in bed. However, he finds inner reserves of strength behind his character's dotty, absent-minded exterior.

Yet despite the three Oscar nominations among the cast, there's hardly any flavor to this thing. Once the movie establishes early on that Iris has Alzheimer's, it's left with no surprising direction to go. Richard Eyre directs in a foursquare manner that might be expected from a director whose background is in television. The movie gives no hint of Bayley's immense learning (his writings on Russian literature are among the best on the subject in our language) and the way he attempted to use it to deal with his wife's illness. Newcomers to Murdoch won't even find out from this movie what kind of books she wrote. A couple as distinguished as this deserves more than what's basically a disease-of-the-week movie, even if they're played by actors as superb as these.