No figure looms over the Civil War as Abraham Lincoln does, and some 17,000 books—from “spiritual biographies” to business management guides—have been published to attest to the fact. The greatest of these were written by Lincoln himself: I mean the countless collections of his speeches, notes, and letters that have appeared regularly and redundantly since 1865.

But the vast majority of lesser books can be traced back to a single volume. Biblical scholars like to talk about “Q,” a long-vanished compilation of the sayings and stories of Jesus that the Gospel writers evidently used as source material in composing their separate accounts. 

Herndon’s Lincoln: The True Story of a Great Life

 (1889) is the Q of Lincoln literature, the wellspring of much of what we know, or think we know, about Lincoln’s character and pre-presidential life. It is a rambling, eccentric, ill-proportioned, and oddly beautiful biography, written by Lincoln’s final law partner, William Herndon.

They were an odd couple. Lincoln called his partner Billy and Herndon called him Mr. Lincoln. Where the senior partner was cool and reserved and ironical, Herndon was high-spirited and earnest and easily swayed. Lincoln never tipped his hand in matters of religion and theology; Herndon shocked the locals of Springfield, Illinois, by loudly declaring himself an infidel and free-thinker. Lincoln was a teetotaler and Herndon drank—episodically but heroically.

Their difference in character was well illustrated when a young man came to their law office bearing a new autograph book. Lincoln wrote simply, “Today, Feb. 23, 1858, the owner honored me with the privilege of writing the first name in this book—A. Lincoln.” Herndon autographed the page in a much larger hand: “The struggles of this age and succeeding generations for God and man—Religion—Humanity and Liberty with all their complex and grand relations—may they triumph and. . . .” It went on from there.

You can't understand Abraham Lincoln without understanding the country that has loved him so.

Herndon loved Lincoln extravagantly, as both friend and statesman. When news of his partner’s murder reached Springfield, where the shingle of “Lincoln and Herndon” still hung outside his law office, he embarked on a journalistic endeavor unique in American historiography: He interviewed or corresponded with everyone he could find who knew Lincoln, traveling from Chicago to southern Indiana and countless hamlets between. Eventually he lapsed into a prolonged period of depression and penury, but with the help of a friendly journalist he was at last able to fashion the mountain of notes and recollections into a book that was published two years before his death in 1891. From it we get the foundational images of Lincoln: the backwoods boy repulsed by his first sight of slavery, the dreamy romantic heartbroken by the early death of his friend and maybe-sweetheart Ann Rutledge, the folksy lawyer with the steel-trap mind.

Some of Herndon’s material has been debunked in its particulars, but with its telling personal details and flavorsome accounts of frontier life—it reads in parts as vividly as a forgotten chapter from Mark Twain’s 

—no reader will doubt the enduring value of “the essential book,” as the Lincoln scholar David Herbert Donald called it. It is impossible for biographers to take on Lincoln without filtering their work through Billy Herndon, whether they know it or not.

Most of them do know it, of course; indeed, the disputes about the contradictions and inconsistencies in Herndon’s source material are likely to be endless. When Benjamin Thomas wrestled with Herndon in his great biography 

 (1952), for example, he rejected the story of Lincoln’s romance with Ann Rutledge as fanciful. Today, several biographers accept Herndon’s account as too good not to be true. Whoever gets the best of the argument, it’s a fact that Thomas wrote a masterpiece, the most readable and reliable one-volume Lincoln biography. He aimed at a general audience, “the Lincoln beginner, . . . the person who can devote only a small portion of his time to learning about Lincoln.” The beginner should begin here. Thomas wore his learning lightly, with a literary flair. And he was probably right about Ann and Abe.

Scholarly entanglements make up a large part of Merrill D. Peterson’s 

 (1994). The book is a history of history: an account of how Lincoln the man and Lincoln the god got all mixed together, from the moment of his martyrdom to the present day. I told myself I would get through this essay without using the cliché “magisterial,” but I’m at a loss otherwise. You can’t understand Lincoln without understanding the country that has loved him so, and Peterson had the gentle touch, wry humor, and scholarly command to tell such a peculiar love story. In all of American historiography there’s nothing else quite like this book, unless it’s another work by Peterson, 

Undeniably great, these three books have earned a place on the top shelf not merely of Lincoln books but of American literature. So you might catch your breath reading the claim made by the historian Allen Guelzo that Harry Jaffa’s 

(1959) is “incontestably the greatest Lincoln book of the 20th century.” But Guelzo is correct, incontestably. Jaffa, who’s still ticking at age 93, is a philosopher, not a historian. It was his mission, as one of his followers (he has followers) put it, to “rescue Lincoln from the historians.” Let the scholar-squirrels tug poor Ann Rutledge this way and that like a wishbone: What make Lincoln Lincoln—what make him inexhaustibly fascinating and supremely important to America and the world—are the ideas that moved him to do what he did.

Jaffa’s book is that rare Lincoln volume that is untouched by Herndon’s mountain of material. His text instead is the transcript of the great debates between Lincoln and Stephen Douglas during the Illinois senatorial campaign in 1858. When Jaffa wrote, in the late 1950s, fashionable historians saw the debates as mere political maneuvering between two ambitious pols; many still do. Jaffa saw something more: a 19th-century version of an argument begun 2,300 years ago, between Socrates and Thrasymachus in Plato’s 

. Justice, said Thrasymachus, was simply “the advantage of the strong over the weak.” Lincoln saw the same wicked principle in Douglas’s “popular sovereignty.”

“Two principles,” Lincoln said, “have stood face to face from the beginning of time, and will ever continue to struggle. The one is the common right of humanity and the other the divine right of kings.” Jaffa’s triumph is to make this grand claim of Lincoln’s a matter of immediate importance. In pursuit of facts, historians can detach themselves from their subjects until a reader is left to wonder what all the fuss was about. Jaffa doesn’t let us off the hook so easily. “If the issue between Lincoln and Douglas was a mere talking point,” Jaffa wrote, “then what justification did Lincoln have to oppose Douglas and bring on such an angry and deep-seated struggle?”

, Harry Jaffa rescued Lincoln’s greatness and, for some of us anyway, made it unassailable. And he did this because he believed that ideas are the motive force in human affairs—the ideas that Socrates pursued, that the Founders embodied, that Lincoln rediscovered in giving his country a new birth of freedom.

 Land of Lincoln: Adventures of in Abe's America (2007).

Andrew Ferguson