wice winner of the Pulitzer Prize, the National Book award, and the Presidential Medal of Freedom, David McCullough is one of America’s great historians. His first book, The Johnstown Flood (1968), dealt with the less-than-enthralling subject of civil engineering, but he still intrigued readers with impressive writing and rich storytelling. His The Path Between the Seas (1977), Truman (1992), John Adams (2001) and The Wright Brothers (2015) earned him acclaim. And he’s also been praised for his narration on TV projects such as PBS’s The American Experience and The Civil War, as well as the 2003 film Seabiscuit.

McCullough’s new book, The American Spirit: Who We Are and What We Stand For, is a stark departure from his previous works. It’s a short, thin volume—rare for modern non-fiction. It features some of his own speeches given between 1989-2016, complete with black-and-white photos and color plates. To the untrained eye, it has the look and feel of a miniature version of a Time Life book on history or art.

But it’s far from that.

This book is a vitally important series of words, paragraphs and ideas about what it means to be an American. “Our history, our American story, is our definition as a people and a nation,” wrote McCullough, “It is a story like no other, our greatest natural resource, one might say, and it has been my purpose in my work to bring that story and its protagonists into clearer, more human focus in what I have written and in speeches I have made.”

McCullough admits he doesn’t remember how many speeches he’s made in his 50-year career. The fifteen speeches chosen for this volume includes several given at university and college campuses and a few at historical sites, and provide unique insights into how certain individuals and philosophies arrived at their place in history. By retracing the powerful footsteps of these remarkable journeys, the nation’s path to greatness shines even brighter.

Here’s a succinct example.

In a speech to a Joint Session of Congress in 1989, McCullough spoke about John Quincy Adams, “who in his lifetime had seen more, contributed more to the history of his time than almost anyone.” When he took a seat in the House of Representatives in 1831, he had “perhaps his finest hours” as he tackled the Mexican War and the gag rule against slavery. In McCullough’s view, Adams “is a reminder that giants come in all shapes and sizes and that, at times, they have walked these halls, their voices have been heard, their spirit felt here.”

McCullough also pointed out that “a book that does justice to the story of Adams’s years in the House,” which he regards as “one of the vivid chapters in our political history, is still waiting to be written as are so many others.” He laments the dearth of adequate biographies about important congressman like Jimmy Byrnes, Joe Robinson, Joe Martin, and Henry Cabot Lodge, Jr., and senators like Arthur Vandenberg, Margaret Chase Smith, and Richard Russell. When considering Congress as a whole, McCullough believes “[w]e need to know more about Congress because we need to know more about leadership. And about human nature.”

Yet, the beginning and the end of this engaging speech had nothing to do with my previous two paragraphs.

Rather, it has to do with the fact that Simon Willard “made a most important clock.” The talented 19th century clockmaker made these hands of time in the foreground of Carlo Franzoni’s Car of History, over the north doorway in Statuary Hall, where the House of Representatives once met. His creation “ticked off the minutes and hours” of the debates McCullough had just spoken about, as well as “the final hours of John Quincy Adams.” The final paragraph sums up this topic perfectly: “It is also a clock with two hands and an old-fashioned face, the kind that shows what time it is now…what time it used to be…and what time it will become.”

McCullough’s exceptional ability to weave historical facts into engaging speeches is on full display throughout The American Spirit.

His 1994 speech at the Independence Day Naturalization Ceremony, for instance, took place at Monticello, whose owner “wrote what is rightly called the nation’s birth certificate.” In McCullough’s view, Jefferson was “an exceedingly gifted and very great man” who “reached for the stars” with the Declaration of Independence, and produced ideas which are “transcendent, as is so much else that is bedrock to what we believe as a people.”

Nevertheless, like many others in the exceptional category of Founding Fathers, Jefferson could also be “inconsistent, contradictory, human.” During his discussion, McCullough asked whether Jefferson was “thinking of black Americans when he declared all men are created equal?” McCullough’s answer was fair and level-headed, “Ideally, yes, I think. Practically, no.”

Meanwhile, at Dickinson College in 1998, McCullough spoke about the life and accomplishments of its founder, Benjamin Rush, arguing that he “ranks among the outstanding Americans of all time.” The brilliant and patriotic physician, educator, politician and “inexhaustible reformer…set things in motion and set an example that couldn’t be more appropriate for this occasion or better medicine for the times we live in.”

McCullough viewed Rush as the perfect example of “animating spirit” for Dickinson College. This occurred in three ways: “goodwill,” “inexhaustible curiosity,” and a “commitment to principle, commitment to service, to his country, and to the fundamental faith that education ought never ever stand still, in the country and in one’s own life.” It appears the debt we owe the man who found a way to end the long-standing hostilities between two former friends, Jefferson and John Adams, is even greater than we imagined.

In 2000, at the 200th anniversary of the White House, McCullough spoke again about its first resident, John Adams, “a great man and a highly principled president in tumultuous times.” His new abode “was still quite unfinished,” with fires that had to keep burning “to help dry the wet plaster,” a scant number of finished rooms, and only one picture on the wall, “Gilbert Stuart’s full-length portrait of George Washington.” When his wife, Abigail, joined him two weeks later, she called it “the castle, and hung her laundry out to dry in the then unfinished East Room.”

Adams would only live in the White House for four months, forced to move out after he lost a bid for re-election against his then-bitter political rival, Jefferson. Yet, he wrote a famous note to his wife that former presidents Franklin D. Roosevelt and Harry Truman greatly treasured—and John F. Kennedy “had the inscription carved into the mantelpiece in marble.” The note was as follows, “I pray heaven, to bestow the best of blessings on this house, and all that shall hereafter inhabit it. May none but honest and wise men ever rule under this roof.” In McCullough’s view, the Adamses would have been pleased by this gathering, to see “the country they so loved still independent, still united and thriving, still strong, still free, and this grand old house looking so magnificent.” Then again, as he pointed out, “maybe they are here with us today.”

While at Boston College in 2008, McCullough discussed the importance of education: “Learning is not to be found on a printout…. It’s not on call at the touch of the finger. Learning is acquired mainly from books, and most readily from great books. And from teachers, and the more learned and empathetic the better. And from work, concentrated work.”

This led to an illuminating discussion about Charles Sumner. He “had shown no particular promise,” and didn’t “distinguish himself as an undergraduate at Harvard.” Yet, he “did love reading” and would eventually put aside his law degree to take courses in France at the Sorbonne. While he was there, he witnessed “how black students were perfectly at ease with and well received by the other students” and “the color of one’s skin seemed to make no difference.” It was this profound experience that led him, many years later, to take a strong stand in the Senate against slavery. As McCullough put it, “[f]rom his quest for learning he brought home a personal revelation he had not anticipated and it changed history.”

Everyone from patriotic individuals to students of history will find something tantalizing to devour in The American Spirit. It may be a small book in stature, but it makes a big—and sorely needed—statement in the realm of intellectual discourse.