The cause was complications of Parkinson's disease, his wife, Marcia Ewing Current, said.

Professor Current had a wide-ranging portfolio as a historian. His first five books, written in the 1940s and early '50s, included a history of the typewriter and a study of Daniel Webster. But over the next 40 years he wrote or edited a number of volumes about Lincoln and his times that elevated him to eminence in Civil War studies, and by the mid-'60s he had joined David Herbert Donald and Don E. Fehrenbacher as groundbreaking leaders of a new, more scrupulous and objective generation in Lincoln scholarship.

"He was a giant in the field from the era that made Lincoln the subject of professional historical study," said Gerald J. Prokopowicz, a former Lincoln scholar at the Lincoln Museum in Fort Wayne, Ind., and now the chairman of the history department at East Carolina University in Greenville, N.C.

Professor Current, who earned a Ph.D. from the University of Wisconsin and taught American history at a number of colleges and universities, established his Lincoln credentials in 1955 with publication of "Lincoln the President: The Last Full Measure," the fourth and final volume of a widely admired biography begun by J. G. Randall. Randall had died with the fourth volume unwritten; Professor Current completed it from Randall's notes, and the book won the prestigious Bancroft Prize in American history, awarded annually by Columbia University.

Previous writers about Lincoln, including Ida Tarbell and Carl Sandburg, were untrained academically, Professor Prokopowicz said, "as opposed to Randall and his successors — Donald, Fehrenbacher and Current." "Lincoln the President" supplanted Sandburg's expansive biography, generally viewed as long on poetic majesty and short on rigorous research, as the standard work of Lincoln scholarship.

Professor Current's next book was "The Lincoln Nobody Knows" (1958), a collection of essays in which he confronted many of the often contradictory arguments about Lincoln and his presidency. (Was he a military genius? A military naif?) The book was known for its judiciousness in considering the validity of previous perspectives on Lincoln and the various claims made about him, many based on questionable recollections of contemporary witnesses. It especially examined Lincoln's evolving thinking on matters of race.

The book did not take Lincoln from the pedestal — Professor Current was a Lincoln admirer — but fleshed out his human complexities.

"Without cynicism but with scrupulous detachment," David C. Mearns wrote in The New York Times Book Review, Professor Current "has produced a learned, lively 'portrait in contrasts' at once provocative, captivating and punctilious. It may well serve as preface and exhortation to scores of monographs not yet begun."

In an interview on Thursday, Mark E. Neely, a Pulitzer Prize-winning Lincoln scholar and a professor of Civil War history at Penn State, said of Professor Current: "Was he a demythologizer? Absolutely. Was he a debunker? No. I like 'The Lincoln Nobody Knows' as well as any Lincoln book I've ever read. The reason is that he presented Lincoln as a problem and not a solution, advanced the idea that Lincoln's legacy was a set of questions, really, rather than a set of answers."

Richard Nelson Current was born in Colorado City, now part of Colorado Springs, into a family known for its longevity. His father, Park, a carpenter, died at 94; his mother, the former Anna Christiansen, at 97. A bone disease, osteomyelitis, contracted as a teenager, left him unable to straighten his right arm and kept him out of the armed services, though not from writing the first draft of his books in longhand. He graduated from Oberlin College and earned a master's from Tufts University before receiving his Ph.D. at Wisconsin.