What if outlaw Jesse James and author Henry James were brothers?

“The James Boys: A Novel Account of Four Desperate Brothers,” by Richard Liebmann-Smith (Random House, $25)

The historian Otis Pease once said the story of 19th-century America could be encompassed in the lives of two sets of James brothers — William and Henry in the east, Frank and Jesse in the west. Debut novelist Richard Liebman-Smith asks: What if all four, intellectuals and outlaws, had been born into the same family?

The mind reels at the possibilities: Full-on historical, in the manner of Larry McMurtry? Postmodern comic gamesmanship, Robert Coover-style?

Or perhaps weighty literary examination, of the kind lately lavished by novelists like Michael Cunningham, Colm Toibin, or Edmund White?

The author seems splendidly equipped to tackle any of these, with a resume that includes stints as editor of The Sciences magazine and Basic Books, and — not least — -co-creator of the madcap Comedy Central cartoon, The Tick.

Alas, Leibman-Smith thwarts his premise by declining to choose.

Not that he doesn't work hard. Fresh off the publication of his first novel, Roderick Hudson, Henry James embarks on a railroad tour of the West. He has just made the acquaintance of Elena Phoenix, a beguiling young women's rights lecturer, when the train is set upon by robbers — led by none other than his younger brothers Bob and Wilky, a.k.a Jesse and Frank, thought killed in the Civil War.

The ensuing story leaps with some nimbleness among its varied subplots and flashbacks, giving us Henry's arduous adventures as a conscripted member of the James Gang; William's struggles against compulsive masturbation as he makes his way as a professor at Harvard; Elena's backstory as a railroad heiress fleeing a sex scandal in staid Hartford, Conn.

Leibman-Smith takes us into the James Gang's Missouri hideout, the ballrooms of Boston, the scholarly offices of Harvard College, and the literary salons of Paris.

He proves deft at mingling historical fact with outlandish invention. Some of the most convincing passages involve exactly how Bob and Wilkie, Union soldiers in South Carolina, rather than dying in battle (as they surely did in history), deserted, made their way to Missouri, and adopted identities as secessionist guerrillas. Liebman-Smith's recounting of the fabled Northfield, Minn., bank robbery, in which the James Gang was shot to pieces by brave townspeople, is downright gripping.

Liebman-Smith is also good at rendering credible and amusing depictions of Flaubert, Turgenev, Cole Younger, William Pinkerton and Charles William Eliot, among other historic personages. personages.i insist on “personage,” which Webster's defines as “a person of distinction or importance”/cm Liebman-Smith is also good at character, rendering credible and funny depictions of Flaubert, Turgenev, Cole Younger, William Pinkerton and Charles William Eliot, among other historic personages.

If Liebman-Smith had fully committed to what “The James Boys” seems most to want to be, he might have produced a classic of 19th-century parody in the tradition of his incomparable “Little Big Man.” Instead, he prefers to wink at the audience.

In naming childhood trauma, for example, as the source of sexual attraction between Jesse and Elena, Liebman-Smith sells it with a nifty mock-19th-century locution: “an abrupt perturbation in the even strata of their development that had set them painfully apart from their peers in late adolescence and subjected them to the scorn of polite society.”

But he cannot stop himself from nudging the reader by declaring them “two horny devils.”

The wise craftsman knows comedy, at times, is best played straight. Next time, sir, decide what kind of book you are writing. And stick with it.