Would you hire this guy?

(Simon & Schuster)

The candidate is hopeless with deadlines and alternates between undisciplined meandering and grandiose hyperactivity. When he isn’t sketching birds, he’s making fruitless plans to reroute rivers, build cities or create absurd flying machines. When he does focus on a project, it’s with a febrile intensity, drawing, say, page after page of triangles or sadistic war machines. More disturbing, he habitually dissects corpses — humans, pigs, whatever’s at hand. He’s restless, moving with proteges and hangers-on from one town to another, leaving contractual agreements unfulfilled.

A risky prospect at best, this mercurial Leonardo from Vinci.

Then again, he did create arguably the two most iconic works of art in Western history: the Last Supper and the Mona Lisa. His drawing of Vitruvian Man is the classic representation of the Renaissance spirit. And if it weren’t for those thousands of pages of forward-thinking sketches on geology, geometry, light, anatomy, astronomy, biblical history, military strategy, hydrodynamics, flight, neuropsychology, ophthalmology and countless other topics, his few surviving paintings wouldn’t be the masterworks that they are. Nor would we know so much about this peculiar, haunted, wonderful man who was, in so many ways, centuries ahead of his time.

He comes to life in all his remarkable brilliance and oddity in Walter Isaacson’s ambitious new biography, “Leonardo da Vinci.” Isaacson’s previous biographical subjects include Benjamin Franklin, Albert Einstein and Steve Jobs — restless, driven men who, like Leonardo, had bisected personalities: one half solitary pioneer, the other half inspirational team leader. For all of them, the unifying element was an insatiable, lifelong appetite for knowledge.

Tinkering and touching up his work for years upon years, Leonardo took quality over quantity to an extreme. He hauled the Mona Lisa around with him, sometimes strapped to a mule, for 14 years, adding a minute speck of new paint here or there until the 30-some layers of brush strokes over a special lead white undercoat on wood vanished into that spookily three-dimensional visage with eyes that follow and a suppressed smile that teases and taunts. Leonardo’s obsessive dissections of lip muscles were key, as were his studies of the eye, to his virtuoso sfumato, a technique of working shades and colors into one another to form indistinct boundaries that feel psychologically subtle and alive.

In “Leonardo da Vinci,” Isaacson’s approach, true to his background, is fundamentally journalistic. No intellectual peacocking for him, and though his writing is certainly graceful, it is never needlessly ornate. But make no mistake: He knows his stuff, crowdsourcing, with extreme diligence, an array of art, historical, medical and other experts to arrive at a vigorous, insightful portrait of the world’s most famous portraitist. Da Vinci groupies won’t find startling revelations here. Isaacson’s purpose is a thorough synthesis, which he achieves with flair.

He seems drawn to da Vinci’s own reportorial instincts. The artist often carried a notebook tied to his belt for his observational sketches as well as his questions, lists, fantasies and jokes. He moved easily among not just artists and musicians (he played the lyre and the flute) but scientists, doctors and engineers, peppering them with questions and sometimes collaborating with them.

Author Walter Isaacson (Aspen Institute)

Isaacson, ever seeking the human aspects of the icons he studies, sieves off as much gelatinous mystique as he can from the obscuring label of “genius.” Charmingly, he ends his book with worthy lessons to be learned from Leonardo. Among these are “be curious, relentlessly curious,” “seek knowledge for its own sake,” “start with the details,” “go down the rabbit holes.” Not listed, but surely helpful, would be “possess a one-in-a-billion innate visual talent” that early on astonished Verrocchio, the Florentine artist with whom Leonardo apprenticed. Isaacson’s vote of confidence in the rest of us is uplifting all the same.

It’s fun when Isaacson occasionally discovers that despite or because of his research, he’s got some opinions of his own, thank you very much. The esteemed art historian Kenneth Clark, for instance, although finding the Last Supper “the keystone of European art,” considered the movement of its characters snapshotty, or “frozen.” “I think not,” pipes up Isaacson in an endearingly rebellious turn. “Look longer at the picture. It vibrates with Leonardo’s understanding that no moment is discrete, self-contained, frozen, delineated, just as no boundary in nature is sharply delineated.” You go, Walter! Don’t let those tweedy types push you around.

If Leonardo’s life reads like a wide-screen epic, that hasn’t escaped Hollywood’s attention. Paramount has bought the rights for a movie adaptation of Isaacson’s book with Leonardo DiCaprio playing his namesake. Here is Machiavelli (oh, please let it be Joaquin Phoenix), lip muscles of his own in full enigmatic, conniving overtime, working his connections with Cesare Borgia and Leonardo. Here’s Francis I, king of France (Russell Crowe or Hugh Jackman?), finally offering to the artist in his final years the no-strings-attached patronage he’s always sought, and cradling Leonardo’s gray-bearded head as he expires. Or not. But it’s a good story, and Ingres couldn’t resist it in his painting the Death of Leonardo.

Where the historical record is a little scant, the imagination kicks in — and Leonardo wouldn’t have had it any other way. Enjoying his own reportorial sfumato, Isaacson writes: “As always with Leonardo, in his art and in his life, in his birthplace and now even in his death, there is a veil of mystery. . . . As he knew, the outlines of reality are inevitably blurry, leaving a hint of uncertainty that we should embrace.”

Alexander C. Kafka has written about books and the arts for The Washington Post, the Boston Globe and the Chicago Tribune.

Leonardo da Vinci

By Walter Isaacson

Simon & Schuster. 624 pp. $35