Toward the end of “Ralph Ellison: A Biography” (Knopf, 566 pages, $35), the important new book by Arnold Rampersad, the reader learns of the “chilly” reception that the aged Ellison gave to “a visitor” in 1983. This visitor, identified only as “a professor from California,” had been trying for three years to interview Ellison about Langston Hughes, the poet who had been one of his most significant early mentors. When the professor finally got his chance, however, he was dismayed to find that Ellison “made no effort to hide his contempt” for Hughes, whose early promise was dissipated in his popularized, politicized later work. Even worse, perhaps, Ellison offered his visitor “no refreshments” — though the visitor learned years later that he had “reported to the IRS an expense of $25 to entertain him.”

If Ellison’s ghost could read this biography, he would surely regret that he didn’t break out the good stuff that afternoon. For of course this unnamed guest, who later had the chance to rummage through Ellison’s tax returns, was none other than Mr. Rampersad, whose life of Hughes established him as one of our leading biographers. Now, almost a quarter-century after that ill-fated visit, and 13 years after Ellison’s death, Mr. Rampersad has written what is likely to become the definitive life of one of the American century’s most brilliant, enigmatic, and unhappy figures. And the further one reads in this skillfully written, deeply researched book, the clearer it becomes that Mr. Rampersad does not like Ralph Ellison.

It is not really Ellison’s stinginess with refreshments that rankles Mr. Rampersad, of course. But the biographer’s meeting with his subject — his only one, it would seem — does have more than personal significance. It points to the deeper flaws that Mr. Rampersad finds in Ellison. By dismissing Hughes’s influence on his own work — “He had taught Ralph little or nothing,” Mr. Rampersad reports — Ellison seemed to sever himself from the history of African-American literature, and in particular from the radical milieu of Harlem in the 1930s, where he first became a writer under the tutelage of Hughes and Richard Wright. Inordinately proud, and reluctant to be grouped with other black writers — instead of with the American and European writers he considered his true peers, like Ernest Hemingway and André Malraux — Ellison left himself open to the charge of arrogance and ingratitude.

At the same time, by dealing ungenerously with a young black scholar, Ellison seemed to cut himself off from the future of African-American literature. No charge is brought more often in Mr. Rampersad’s book than Ellison’s repeated failure to do anything to help younger black writers, even those who greatly admired him. Mr. Rampersad seems to have spoken to everyone who ever tried, and failed, to get Ellison to give them a blurb or a letter of recommendation. The most eminent of the disappointed, Toni Morrison, can speak for them all. When she was elected to the American Academy of Arts and Letters, of which Ellison had long been a member, “he made no attempt to make me feel welcome. At the first meeting I attended, he … never said hello.”

He never said hello: this could be the motto of Mr. Rampersad’s biography, a kind of legend for a kind of tombstone. It is not, perhaps, the worst of crimes to be unfriendly, even haughty — at any rate, it is a crime of which many writers much less eminent than Ellison have also been guilty. Nor are the other misdemeanors which Mr. Rampersad lays to Ellison’s account particularly shocking for a writer of his generation — the generation of hard-drinking, womanizing, often unamiable figures like Saul Bellow and Robert Lowell.

Yet page by page, Mr. Rampersad works to undermine the sympathy that it should be a biographer’s mission to create. Right from the start, Mr. Rampersad lets us know that Ellison was not nice enough to his mother. While he was off at college at the Tuskegee Institute, he kept writing home asking for money, even though his mother was struggling to earn a living in the depths of the Depression. He was not close to his brother, who was mentally handicapped, and whom he saw only a handful of times during their adult life. He had an affair that deeply hurt the feelings of his second wife, Fanny, his companion and caretaker through his years of fame.

It is not in his description of these large, common flaws, however, that Mr. Rampersad’s disappointment really shows itself. Rather, we sense it most clearly in the descriptions of foibles so petty that another biographer might not mention them at all. He repeatedly takes Ellison to task, for example, for accepting expenses-paid junkets, rather than paying for his own vacations. He needles him for watching Masterpiece Theater on PBS (“although the ‘masterpieces’ were often high-toned soap operas”). The deadliest thrusts hide under a cloak of objectivity. Discussing Ellison’s collection of African art, Mr. Rampersad begins one sentence with: “If some people saw collecting art objects as a bourgeois affectation …”

Most vicious of all is Mr. Rampersad’s off-hand description of Ellison’s election, in 1964, to the Century Association, the Manhattan arts-and-letters club that became his favorite haunt in later years. “At fifty,” Mr. Rampersad writes, “he was atop that part of the world about which he cared the most. America was rumbling with social discord, belching fire, and his second novel was not under control. But overcoming the many handicaps and setbacks in his life, Ralph had secured a place for himself near the top of his Mount Parnassus.” There he was “in a comfy armchair or on a plush leather sofa, a martini in one hand and a fat cigar in the other.”

This quietly vindictive passage encapsulates the bitterness that many younger black writers felt toward Ellison in the second half of his life. Until 1952, when he published “Invisible Man,” Ellison was much easier to admire, if even then hard to love; and the first part of Mr. Rampersad’s book is far more enthusiastic and absorbing than what follows. Prickly, reserved, and earnest, Ralph Waldo Ellison had vast ambitions even as a child in Oklahoma City, where he was born in 1913. After his father died, when he was three years old, Ellison’s childhood was shadowed by poverty. Yet he dreamed of becoming a great composer, studying trumpet and piano and winning a place in the Tuskegee band.

It wasn’t until 1936, when he dropped out of Tuskegee, disgusted with its provincialism, that he began to shift his ambitions to literature. He arrived in Harlem that summer and plunged into its literary and political ferment. Soon he was an ardent fellow-traveller, if not an actual Communist Party member, writing stories for New Masses and getting to know Wright and Hughes. Then came the Nazi invasion of the USSR, and the Party’s quick decision to drop its civil-rights agitation in favor of urging America to enter the World War II. Disillusioned, Ellison began the intellectual journey that would lead him to the anti-communist left, and to a new home in the largely Jewish milieu of Partisan Review.

Ellison first began work on the book that became “Invisible Man” in 1945. When the novel finally appeared, seven years later, it was not a huge commercial success — it did not sell nearly as well as “Native Son,” Wright’s massive hit — but it was a critical darling, winning the National Book Award. And it was the rare prize-winner whose reputation has only grown with time. By the time Ellison died, in 1994, his novel was securely established as an American classic, on the same short list that includes “Moby-Dick” and “The Great Gatsby.”

This does not mean that “Invisible Man” is ageless. Today, the book’s obsessive symbolism and its African-American version of existentialism feel very much like artifacts of the 1950s. There is something willed and programmatic about Ellison’s use of mythic tropes. When Jim Trueblood recounts his original sin of incest, for example, Ellison makes sure there is an apple on hand. (Ellison’s admiration for the critic Kenneth Burke helped to form his conception of the novel as “symbolic action.”)

Yet the very bluntness of Ellison’s symbolism contributes to the book’s urgent absurdism, which perfectly reflects the urgency and absurdity of America’s racial predicament. “Invisible Man” is a great novel, despite its obvious flaws, because it takes risks — political, psychological, literary — that are still breathtaking today, in our much changed racial climate. It makes sense that Ellison himself regarded the writing of “Invisible Man” as a sustained gamble: he was “playing a game with myself,” he said, “the game of discovering whether I could write a novel.”

“Invisible Man” proved that he could write a novel, and a great one, but notoriously, he could not write another. The year 1953, when Ellison won the National Book Award and began his career as a collector of prizes and professorships, was the high point of his life, and its turning point. Thereafter, inevitably, Mr. Rampersad’s biography loses its zest, as Ellison goes from active writer to mere literary lion. The chapter titles tell the story: “Annus Mirabilis” is followed by “Second Act,” “Hanging Fire,” and “The Monkey on His Back.”

Ellison produced a classic essay collection, “Shadow and Act,” in 1964, and another, “Going to the Territory,” in 1986. But of the long-promised second novel, which he worked on unceasingly, there was nothing but occasional excerpts, of steadily diminishing coherence and value. When the book “Juneteenth” (1999) was carved out of a massive manuscript after his death, it was a damp squib, a confirmation of futility.

To Mr. Rampersad, this prolonged failure, which caused Ellison unspeakable pain, carries an obvious moral. It was retribution for his betrayal of solidarity, his refusal to be more generous, more rooted, more in tune with the times. His aloofness, Mr. Rampersad writes, “was stirring up a growing dislike of him among younger blacks that added to his sense of isolation and made the task of creating art more difficult than it already was.” The more Ellison seemed to prefer the esteem of whites to that of blacks, Mr. Rampersad argues, the more he cut himself off, Antaeus-like, from the ground of his strength.

This may indeed be part of the answer, but to make it the whole answer is to risk simplistic political moralizing, of a kind that Ellison particularly disliked. To fully explain Ellison’s aloofness from younger black writers, and from the more radical phases of the civil rights movement, one has to take seriously his high liberal principles, borne of his experiences with communism; and his insistence on viewing African-American literature as a part of Western literature, to be judged by the highest possible standards. One must also enter more sympathetically than Mr. Rampersad is able to do into the costs of Ellison’s personal pride, forged in response to both white racism and what he perceived as the condescension of the black establishment. (No reader of “Invisible Man” can forget Ellison’s searing attack on “the college” and its god-like “Founder,” based on Tuskegee and its cult of Booker T. Washington.)

Together, these factors made Ellison deathly afraid of committing himself to any follow-up to “Invisible Man,” which would almost inevitably be a letdown. The most convincing explanation for Ellison’s fate is offered by Stanley Crouch, one of the late-life friends quoted by Mr. Rampersad: “The tragedy lies in the weight Ralph put on himself. He created this grand tower in his mind, with a priceless penthouse at the top, which was virtually impossible to climb.”

Ellison assumed that crippling burden, in part, because he felt that it was his responsibility to prove that black genius could and should be measured by the same standards as every other kind of genius. In this sense, his long silence was the price Ellison was doomed to pay for America’s racial madness — the very madness he brilliantly captured in “Invisible Man.” By documenting Ellison’s life so thoroughly, Mr. Rampersad has done him an important service, but he is not generous enough to do Ellison justice.