"I'm very interested in people your age because I think you're very smart and can learn things very fast," says McCullough, 71, who has arrived on this recent afternoon at the request of his grandson, fifth-grader David McCullough III.
For an hour, the courtly, white-haired author, wearing a dark jacket and tie, engages the children, most of whom wear T-shirts. He quizzes them and they quiz him, asking when he wanted to become a writer (as a child) and did he ever begin a book and abandon it (yes, a biography of Picasso). They applaud when he finishes and he beams when asked if he enjoyed his visit. "Did I ever!"
As his latest book, "1776," arrives in stores, he's been thinking a lot about the birth of the country and what people know about it. The kids at Josiah Haynes seem pretty on top of their studies, even though not all know why 1776 is important. But McCullough worries that the United States is in a deep and dangerous crisis.
"I find it terribly sad and worrisome when I meet people who come here from elsewhere in the world and know more about American history than people I talk to on college and university campuses," he said earlier in the day, during an interview at the historic Longfellow House in Cambridge, Mass.
He is an agreeable man who prefers writing about people he likes -- he tells the students that choosing a subject is like picking a roommate -- praises scholars and popular historians and gets along with liberals and conservatives.
But education is one issue on which he takes sides. Worried that the No Child Left Behind act has emphasized reading and math at the expense of other subjects, he is one of dozens of historians who signed a petition asking Congress to increase funding for history.
He also helped persuade Congress to approve the building of a John Adams monument and was instrumental in raising money to restore the Longfellow House, a pillared mansion that served as headquarters for George Washington in 1775-76 and was a key resource for McCullough's new book.
"People didn't know what kind of shape this house was in. It took someone like David McCullough to put the word out," says Jim Shea, site manager for the National Park Service, which has managed the Longfellow home since 1972.
No living historian has more power to popularize a subject simply by writing about it than McCullough. His last book, "John Adams," heightened the subject's reputation and almost single-handedly established a large market for books about the founders.
Best sellers since "John Adams" include David Hackett Fischer's "Washington's Crossing," which recently won the Pulitzer for history; a pair of Benjamin Franklin biographies, by Edmund S. Morgan and Walter Isaacson; Joseph Ellis' "His Excellency," a book about George Washington; and Ron Chernow's "Alexander Hamilton."
"I have been asked countless times why there is this vogue for books on the founding fathers," says Chernow, whose next book will be a biography of Washington. "I have contrived all sorts of fancy and esoteric explanations for the phenomenon, but I could also make the argument that the answer boils down to two words: David McCullough."
McCullough's research on Adams inspired him to write "1776," which he calls a "companion" to that biography. His new work has an announced first printing of 1.25 million -- enormous for a history book -- and will surely be the biggest Revolutionary War title since "John Adams," which won the Pulitzer in 2002 and has sold more than 2 million copies.
With the release of "1776," publishers and booksellers are betting that colonial era books will rise again. New titles include a John Adams biography by James Grant and a Thomas Jefferson book by Joseph Wheelan. Stacy Schiff, author of the Pulitzer Prize-winning "Vera," has written "A Great Improvisation," about Benjamin Franklin in Paris.
"This ('1776') is not one of those books where you finish it and say, 'On to the Civil War.' You're going to be looking for everything available about that time in history," says Bob Wietrak, vice president of merchandising for Barnes & Noble, Inc.
Like "John Adams," most of the best sellers have been biographies of the principal founders. "1776" differs in a few ways: It is the portrait of a time, as opposed to an individual, and its emphasis is not on politics, but on war.
While 1776 will forever be identified with the Declaration of Independence, McCullough only briefly refers to it and to Tom Paine's "Common Sense," the most influential political pamphlet of the time. Instead, he writes extensively about the Siege of Boston, which ended with American troops freeing the city from British occupation, and the disastrous Battle of Long Island, when the revolution seemed on the verge of extinction.
McCullough believes in the power of "great men and women" to make history and George Washington is the hero of his book. But "1776" also acknowledges the lesser-known. The author cites Jabez Fitch, a young lieutenant from New York whose diaries chronicled his brutal treatment as a prisoner of war, and John Glover, a Massachusetts commander who helped Washington's battered army escape the British by ferrying them from Long Island to Manhattan.
"A lot of what I've done in my books is try to give credit where credit is due," McCullough says. "I feel strongly that when we celebrate the 4th of July, when we talk about the spirit of '76 ... it's too often only recalling people who were at Independence Hall (in Philadelphia) that summer and the political drama. In fact, none of that would have amounted to more than words on paper had it not been for what these other people were doing."
McCullough, whose father and grandfather founded the McCullough Electric Company, was born in Pittsburgh in 1933. He loved history as a child, recalling lively dinner conversations, portraits of Washington and Lincoln that seemed to hang in every home and the field trip to a nearby site where Washington fought one of his earliest battles.
He majored in English at Yale University and worked at Sports Illustrated and the American Heritage Publishing Company before deciding that he wanted to write about an event that took place in his home state, the Johnstown Flood of 1889. Encouraged by his wife, Rosalee, who still serves as his main collaborator, McCullough researched the book in his spare time and "The Johnstown Flood" was published in 1968.
He followed with "The Great Bridge"; a book about the Panama Canal, "The Path Between the Seas"; and a work on the early years of Theodore Roosevelt, "Mornings on Horseback." His real breakthrough came with "Truman," a million seller that won the Pulitzer even as some critics complained that he had idealized his subject.
Beyond his books, McCullough may have the most recognizable presence of any historian, his friendly baritone known to viewers of "The American Experience" and to fans of the movie "Seabiscuit," which he narrated. Chernow calls him "both the name and the voice of American history."
After completing "John Adams" and "1776," McCullough jokingly told his wife that he likes the 18th century so much that he might never want to leave: He loves the idealism and the art, citing such writers as Samuel Johnson and Tobias Smollett; he appreciates the way people lived.
"We have no idea how difficult an ordinary day was, even in peacetime," he says. "We're softies compared to those people. We see them in their ruffled shirts and their satin jackets, knee buckles, powdered hair and the rest. They look like fops. But they weren't. They were very resilient and hardened by life."
So much reminds McCullough of the past, and what he has to be thankful for, even the terrorist attacks of Sept. 11, 2001.
"I was very annoyed hearing people say, 'This is the darkest, most dangerous time we've ever been through.' Well, anybody who says that has no sense of history and what we have been through," he says.
"About 25,000 Americans died in the American Revolution. That doesn't seem like very much to us, but it was 1 percent of the population. If that were true today, it would be over 3 million people. If we were in a war that lost 3 million people, wouldn't we think that was pretty bloody? Pretty important?
"History is an antidote to the hubris of the present. We think we're so terrific. We think we know so much. We think we have such genius. Well, think again."