The modern biographer hails Thomas Eakins as a kindred spirit. His masterpiece, “The Gross Clinic” (1874), one of the towering achievements in world art, parallels the new spirit of inquiry and candor that distinguishes the 19th century’s greatest biography, James Anthony Froude’s “Life of Carlyle.”

While many cutting-edge artists were turning away from realism and biographers lapsed into panegyric, Eakins and Froude took a scalpel to portraiture, opening a vein of verisimilitude that their contemporaries found shocking. Carlyle’s friends and family attacked Froude on all sides for, in effect, vivisecting the Victorian sage’s troubled marriage. The art establishment censured Eakins for depicting an actual operation, in which Dr. Gross’s assistants removed a diseased bone while he stood, bloody scalpel in hand, apparently addressing students in the operating theater of Philadelphia’s Jefferson Medical College. Both Eakins and Froude brought down upon themselves the wrath and disgust of an age that revered reticence and considered the intimacies of the body and the psyche a strictly private matter.

Froude was never able to recover his reputation, while Eakins saw his greatest work shunted aside and many of his ruthlessly honest portraits destroyed by their subjects or their families. This greatest of all American painters never had a one-man show and only began to receive his due when Lloyd Goodrich published his groundbreaking biography in 1933.

Sidney Kirkpatrick pays handsome tribute to Goodrich in the introduction to “The Revenge of Thomas Eakins” (Yale University Press, 566 pages, $39.95), as he does to art historians and critics who have completed Eakins’s “revenge” on the art establishment of his time, aghast that he insisted on posing women and men completely nude in his classes and portrayed the human anatomy with such intricate – indeed clinical – care that 19th-century viewers deemed virtually pornographic.

Eakins never compromised his vision of art and was fortunate to have a father who supported his son’s choice to go his own way. Like Dr. Gross, in whose classes Eakins studied anatomy with an avidity that would have made him a great surgeon (so said one of the artist’s other medical professors), Eakins thought of himself as a pioneer, shaping the modern perception of human form and of portraiture.

As Mr. Kirkpatrick points out, “The Gross Clinic” is no easy painting to read, even though its subject matter is obvious. This monumental work (nearly 8 feet tall and 7 feet wide) is full of mystery. Who is the patient? Only an exposed knee and part of a lower leg are visible. And while Dr. Gross’s four assistants crouch over the body wielding surgical instruments as students in the background behind Dr. Gross observe the operation, a female figure to Dr. Gross’s lower right raises her clenched hands against her face in terror.

What is going on? The details have to be perused again and again.The painting’s realism is balanced by a calculated symmetry. Dr. Gross, for example, holds his scalpel like one might grasp a pen. In the operating theater he is describing his procedure, while a student seated above him pens his notes.The operation, in other words, becomes a kind of narrative as Eakins conflates portraiture with storytelling and scene setting.

But what about that female figure? What is she doing there? Certainly her horror acts as a counterpoint to the surgeons, unfazed by the bloodletting, and her reaction to carnage is understandable. Surely one way to view this riveting work is to consider it a mediation on what it means to be a surgeon, and what it means to be an unflinching portraitist.

To read further into the painting is to call on the indispensability of biography. The terrified woman is, in fact, the patient’s mother. Her presence was, in fact, obligatory. Law stipulated that a member of the family had to be present at surgeries involving charity cases.

Although Mr. Kirkpatrick does not acknowledge as much, to me, as a biographer, the painting seems a parable about biography.The incisive biographer, like the surgeon, penetrates to the bone, often provoking the outrage and grief of the subject’s family. Offended reviewers like Joyce Carol Oates even coined terms like “pathography” to denigrate the clinical nature of modern biography, as one of Eakins’s contemporaries called “The Gross Clinic” a “degradation of art,” saying it could only be redeemed by wiping away the blood on the canvas.

Like surgeons, biographers have blood on their hands.They strip their subjects bare to reveal their anatomies. Like James Boswell, Froude was constantly amazed that certain readers objected to his frank inquiries and did not see, as he did, that only the truth – not people’s sensibilities – mattered.

Mr. Kirkpatrick, an exemplary biographer, demonstrates how an understanding of Eakins’s greatest painting puts the viewer in league with the painter: “Once the viewer is involved, the bloody detail sweeps over the viewing experience in ways that few paintings ever achieve.” In other words, the painting becomes a part of the viewer’s own operating theater. The painting is ultimately about Eakins’s own relentless pursuit of truth through art, Mr. Kirkpatrick concludes.

Like his subject, Mr. Kirkpatrick is relentless in the best sense of the word, dispassionate and objective in a surgically precise way, and yet completely involved, investing his subject with a pathos and grandeur that only the finest biographies attain.

crollyson@nysun.com