You’d think that the vital but thankless and tedious process of editing a book wouldn’t make much of a movie. And you’d be right.

“Genius,” about the greatest editor of them all, Maxwell Perkins, is all dimly-lit offices, train rides and sitting in one’s living room after the kids have gone to bed, marking up pages and pages and pages with a red pencil.

Even the promising character study of a man, played by Colin Firth, content to do Herculean labors in the shadows of the likes of F. Scott Fitzgerald, Ernest Hemingway, Erskine Caldwell and Thomas Wolfe, feels superficial, dry and somewhat unsatisfying.

But actor-turned-director Michael Grandage’s debut feature bubbles to life thanks to casting.  Guy Pearce is a blocked, forgotten but plainly brilliant Fitzgerald, Dominic West puts his stamp on 1930s vintage “Papa” Hemingway, and Jude Law, all manic energy, vomits up paragraphs and pages and more pages of the purplest prose as Wolfe, the tempestuous relationship that is the heart of this story.

Wolfe desperately wants to be published, to release his “little testament, faith cast out into the dark night.”

It was the toughest editing job the legendary Perkins ever took on — shaping the fiction of a wildman of letters of the North Carolina mountains whose rough drafts deforested whole states. Turning 5000 pages into “Of Time and the River,” or rendering the mad meandering navel gazing of “O, Lost” into a Great American Novel — retitled “Look Homeward, Angel”were Perkins’ severest tests, and it is suggested, his most rewarding.

Law’s Wolfe is brash, needy, rude and drunk much of the time. He is in awe of Fitzgerald until Perkins agrees to edit and publish him. Suddenly, Wolfe is overly familiar with the “Great Gatbsy” novelist, cruel to Scott and his mentally unstable wife.

Nicole Kidman is just the right touch of theatrical as stage designer Aline Bernstein, Wolfe’s married lover and sponsor. Wolfe grasps at the hem of her skirt until instant fame arrives. His “sweet Jewess” bridles at being shunted aside for his new “love,” Perkins — the man who will make all his dreams come true.

Laura Linney plays Mrs. Perkins, long-overshadowed mother-of-five and wife to a confirmed workaholic. Perkins is so wrapped up in the important business of “putting good books in the hands of readers” that he never, ever takes off his fedora. He’s a mild-mannered Walter Winchell, living vicariously through the mercurial Wolfe, always seen in his hat.

A telling scene straight out of Screenwriting 201: Defining Characters, pairs the two up at a Harlem speakeasy, with Wolfe comparing his “grandiose” and verbose style to jazz, and Perkins confessing an affection for the squarest tune of all time — “Flow Gently, Sweet Afton.”

Law’s Wolfe is a “monster,” “Caliban,” he says, comparing himself to Shakespeare’s troubled servant/beast of “The Tempest.” He sucks all the oxygen out of any room, and Firth has a hard time registering as anything other than a dull pedant in awe of Wolfe’s prose and way of devouring life.

The relationship is so uneven that the lovely, muted colors that recreate the period, the dazzling casting all around and Law’s breathless way with a Wolfeian phrase barely right the scales.

“Which of us is not forever a stranger and alone?” he asks in a florid Carolina drawl. “Ghost, come back again!”

Law’s overpowering performance is funy, but “Genius” adds up to just a little more than a lovely bore. And any hint that Perkins was the “true” genius never pulls clear of the shadows cast by the blinding light of Law’s Wolfe.

MPAA Rating: PG-13 for some thematic elements and suggestive content

Cast: Colin Firth, Jude Law, Nicole Kidman, Laura Linney, Dominic West
Credits: Directed by Michael Grandage, script by John Logan, based on the A. Scott Berg biography. A Summit/Roadside Attractions release.

Running time: 1:44