Lincoln's address at Cooper Union is the most important speech he made that historians have written the least about. In it, the presidential longshot from Illinois persuasively but dispassionately refuted an argument that many Americans still accept as fact today: that most of America's founding fathers supported the perpetuation of slavery. Less than three months after delivering the speech in February 1860, Lincoln would snatch the Republican nomination from a field of almost a dozen candidates; in nine months, he would win the White House without a single Southern electoral vote.

Now, after being neglected or misunderstood by historians for more than a century, the Cooper Union address is the subject of two books with almost identical titles (and covers)--one by a premier Lincoln historian, the other by a self-published amateur. The first mentioned, by Harold Holzer, benefits from the author's superior academic pedigree, which includes almost two dozen previous books on Lincoln and the Civil War. The second, written by Bronxville, N.Y., lawyer John A. Corry and first published by Xlibris last November, admirably holds its own, however, both for its readability and as a striking example of the professional quality of which on-demand publishing is now capable.

Despite the books' similar titles and appearance, the authors differ markedly on matters of interpretation as well as historic fact. Holzer argues convincingly that Cooper Union alone propelled Lincoln into the White House, whereas Corry remains skeptical, pointing out that masterful maneuvering and promises of patronage by Lincoln operatives at the Republican convention were also crucial. Then there's the legend that two prominent Chicago newspapermen heavily revised Lincoln's speech on his way to New York only to have all of their suggestions rejected by the Springfield lawyer when he delivered the final address. Holzer dismisses the story as myth because it doesn't fit Lincoln's train schedule; Corry accepts it, however, based on quotes from Carl Sandburg's biography (a notoriously unreliable source). And yet, the tale contains too much detail and is too embarrassing to the two newspapermen who told it to be either a total fabrication or the product of embellished memories.

Both books contain helpful appendices featuring Lincoln's full speech, annotated with historical references, and Corry's book adds the text of two letters, previously unpublished, that shed new light on the confusion over who first invited Lincoln to New York. Regardless of the differences between them, both books succeed in bringing long-overdue attention to a pivotal Lincoln moment, without which the United States would be neither united nor the most powerful nation on the face of the earth.

Lincoln at Cooper Union: The Speech That Made Abraham Lincoln President

by Harold Holzer (Simon & Schuster, 338 pages, $25)

Lincoln at Cooper Union: The Speech That Made Him President by John A. Corry (Xlibris, 282 pages, $21.99)