Hardly any figure in American history attracts such extreme judgments as Ulysses S. Grant. He led Northern armies to victory in the Civil War, and his contemporaries gave him credit along with Lincoln for saving the United States. They elected him President just three years later and then re-elected him by a wide margin, entrusting him to continue reconstruction of the South – probably the most daunting democratic “nation-building” project ever undertaken.

When Grant died in 1885, his fellow citizens revered him as one of the greatest of Americans, and his memoirs, published that year, became one of the bestselling American books up to that time. Even as late as 1922, more than a million citizens attended the dedication of the tomb built in his honor in New York City, where he was laid to final rest with his beloved Julia. Yet by that time a new, and decidedly less pleasant image of the man, had taken root.

From the 1880s (when the “Lost Cause” began to be resurrected by Southern writers like former Confederate General Jubal Early) to the 1930s, the majority of writers depicted Grant the general as an unskilled butcher, Grant the President as a corrupt despot or a bumbling incompetent, and Grant the man as dim and inarticulate (when not inebriated). Grant’s life had three remarkable acts: general-in-chief, president, and masterful writer of his “Personal Memoirs.” But this leader of men, champion of racial justice, and accomplished writer is now remembered for scandals in which he was never personally involved.

How such opinions so quickly became the standard view is a good story in itself, and several new books help to tell it. For those new to the Grant literature, they also offer a convenient entry point. But the books exemplify both the bad and the good of Grant scholarship through the years.

For Act 1, “A Victor, Not A Butcher: Ulysses S. Grant’s Overlooked Military Genius” by Edward H. Bonekemper III (Regnery, 480 pages, $27.95) gives us both a good Civil War narrative and a convincing analysis of Grant’s military strategy, while Michael Korda’s compact biography, “Ulysses S. Grant: The Unlikely Hero” (HarperCollins, 176 pages, $19.95) provides a succinct and exciting summary of this crucial time.

For Act 2, Josiah Bunting III’s compact biography “Ulysses S. Grant” (Times Books, 208 pages, $22.95) devotes more than the usual space to his presidency, arguing that Grant belongs far above the bottom ranks to which he has traditionally been assigned.

Finally, for Act 3, Mark Perry’s “Grant and Twain: The Story of a Friendship that Changed America” (Random House, 336 pages, $29.95) gives an absorbing account of the remarkable 15-month period (1884-85) during which Grant wrote his “Personal Memoirs,” regarded by many as America’s greatest work of nonfiction, and Mark Twain completed “Huckleberry Finn,” perhaps its greatest work of fiction.

Southern writers eager to preserve Robert E. Lee’s reputation promulgated the notion that the North won the Civil War by mindless application of greater manpower and industrial strength, not by superior generalship, and that Grant’s only distinction is that he understood how to bludgeon. This stereotype does not fit the facts; nor is it any longer the mainstream view of military historians. Mr. Bonekemper rightly attacks it.

Grant’s methods emphasized bold movement, speed, and surprise rather than sheer mass; campaigns rather than battles; flexible adjustment to varying circumstances rather than repetitive application of a simple formula. Rather than killing armies, he preferred, if he could, to capture them or destroy their supply lines and bases of operation.

Astonishingly, a total of 78,000 men in three different armies surrendered to Grant during the war; no other army surrendered to anyone except Sherman, under Grant’s command. Grant used attrition against Lee for five weeks in 1864 because it was the only feasible counter to Lee’s skillful use of entrenchments and the only way to keep Lee from detaching forces against Sherman.

Mr. Bonekemper’s estimation of Lee is in my opinion too low, but his interpretation of Grant reflects the cutting edge of current research. Mr. Korda also writes with an eye to the present, praising Grant for having “defined for all time the American way of winning a war, from which, nearly 150 years later, we deviate at our risk.” He does not attempt to marshal arguments, but writes swift-moving, engaging prose with a personal edge. His book, however, is an example of how the posthumously unlucky Grant continues to be misunderstood.

Mr. Korda relies heavily on two secondary sources — a 1928 biography of questionable reliability and William S. McFeely’s “Grant” (1981). The McFeely was at one time the “definitive full biography” but of interest now as an example of the condescension to which Grant was once subjected. In his final chapter (titled “Why Grant?”), Mr. Korda implies that Grant would have disapproved of the Iraq war. Set aside that unanswerable question; the Civil War is the relevant one here, and Mr. Korda’s argument shows that the condescension continues.

Mr. Korda thinks America’s winning strategy has always been old-fashioned bludgeoning. In fighting Lee, Mr. Korda claims, Grant “simply calculated that the North had a larger population than the South, that he could therefore afford casualties better than Lee could in the long run.” In addition, he believed that “the American armed forces ought to be used only when there is strong civilian support in favor of their use, and then used in overwhelming numbers, bringing American’s vast industrial resources and strength to bear on the enemy for a quick, crushing, and complete victory, and then bringing the troops home again as soon as possible.” (In other words, the Powell Doctrine.) This ignores two important traits widely attested to by Grant’s contemporaries.

First, Grant was famous for dogged persistence in the face of obstacles, setbacks, and mistakes. During the Civil War and Reconstruction, those obstacles included unreliable public support. There were the Draft Riots in New York, and in the summer of 1864 several military victories gave Lincoln a boost he desperately needed to defeat a Democrat, George McClellan, who would be expected to negotiate peace with the Confederacy. Grant responded actively rather than passively to public opinion: He made sure that Sherman took Atlanta and won Lincoln the election.

Second, Grant was willing to fight with available resources. He was not at all inclined, like other generals, to wait for overwhelming force or perfect intelligence. More than once, he disregarded or acted without orders from risk-averse superiors. He was always on the offensive; even when his own troops were exhausted, he calculated that the enemy was probably worse off. He did not rest or consolidate after a battle, but moved on to attack the enemy at the next weak point, to keep it off balance and eventually wear it out.

When Grant had the resources, he moved on multiple fronts, to stretch the enemy’s manpower and resources to the breaking point. Grant might well have wondered why the United States would not apply pressure in both Iraq and Afghanistan, as well as elsewhere. He would be unperturbed by temporary setbacks but alert for indications (such as reduced frequency or shifting locations of major attacks) that terrorist networks were being stretched thin.

Mr. Bunting’s biography, like Mr. Korda’s, lends itself to a casual read. But it is far more up to date on recent Grant research, drawing from Frank Scaturro (“President Grant Reconsidered,” Madison Books, 1999), Brooks Simpson (“Let Us Have Peace,” University of North Carolina Press, 1997), and Jean Edward Smith (“Grant,” Simon & Schuster, 2002), who have argued for a positive reappraisal of Grant’s presidency. Indeed, Mr. Bunting asserts that only the challenges faced by Lincoln and Franklin Roosevelt compare with those Grant came up against.

Although Grant had significant accomplishments in foreign affairs and economic policy, his paramount objective as president was to secure the gains of the Civil War. This meant, primarily, restoring democratic government in the South while ensuring the rights of freedmen against the resistance of the white population. But it also meant preserving a Republican national majority, which was threatened by reunion with the Democratic South.

Grant saw the solution with characteristic clarity: Both civil rights for freedmen and the future of the Republican Party could be secured only if the right of the freedmen to vote was enforced by the federal government and converted into political power. Again, Grant was not afraid to act decisively. He was the last president until Lyndon Johnson to propose and pass civil rights legislation. He was the last until Eisenhower to send troops to a Southern state to suppress terrorism and guarantee minority rights.

Eventually, pro-Reconstruction Radical Republicans grew weary of endless “Negro troubles” and liberal Republicans changed the subject from civil rights to corruption. Southern historians long reviled Grant for pursuing a foolish chimera (racial equality) by brutal and unconstitutional methods. In the 1960s, by contrast, Grant was unfairly blamed for abandoning civil rights. But it is a tribute to Grant’s political courage that troops were still in the South when he left office; his successor, bowing to a less attractive political reality, withdrew them. Grant was determined and flexible in the pursuit of racial justice, as he was in winning the Civil War, but in the former case he was 100 years ahead of the country.

Mr. Perry’s book makes clear that besides being friends, Grant and Twain were both moved by the problem of racial relations in the South. Though they were very different, both could be funny – the introvert Grant had a sly wit, the extroverted Twain aimed more directly. Grant showed superhuman courage as he raced cancer to complete his writing. And Twain, as publisher, acted with integrity and friendship to help Grant achieve the real objective, ensuring his family’s financial future.

Grant’s “Personal Memoirs” were not simply a commercial success. Matthew Arnold wrote an early appreciation. Edmund Wilson would later call the book “the most remarkable work of its kind since the ‘Commentaries’ of Julius Caesar.” The prose in the “Memoirs” is precise, concrete, objective, and somehow at the same time expressive of the whole man, including his humor.

As John Keegan says, this is a good place to go if you want to understand why the North won the Civil War. And it is still the place to go if you want to get to know Ulysses S. Grant.

Mr. Cohen is the president of Cognitive Technologies Inc. in Arlington, Va.