On a dark and windy morning on the Outer Banks of North Carolina, 114 years ago this Sunday, Orville Wright took flight in a tiny airplane he and his brother Wilbur had painstakingly constructed. The 605-pound craft flew all of 120 feet and remained airborne only 12 seconds. After Orville’s first success, Wilbur set the record for the day: He flew a little more than half a mile in 59 seconds. Their flights seem almost absurdly brief. Yet they made history.

December 17, 1903, was “the beginning of change for the world far greater than any of those present could possibly have imagined,” writes historian David McCullough in “The Wright Brothers,” his 2015 best-seller. With their “homemade machine, Wilbur and Orville Wright had shown without doubt that man could fly.”

McCullough carried out much research for the book in the Wilbur and Orville Wright Papers at the Library of Congress:

Rare is the collection that provides so much depth and range, and all in such detail. In a day and age when, unfortunately, so few write letters or keep a diary any longer, the Wright Papers stand as a striking reminder of a time when that was not the way and of the immense value such writings can have in bringing history to life. Seldom ever did any of the Wrights—father, sons, daughter—put anything down on paper that was dull or pointless or poorly expressed. And much that they said to each other, and only to each other, was of great importance. In all, the family letters in the Library’s collection number in excess of a thousand. In addition, there are their large scrapbooks, a gold mine of insights.

The Wright Papers were donated to the Library by the executors of Orville Wright’s estate after his death in 1948. The Library received additional Wright material by gift, transfer and purchase from various sources between 1949 and 2002.

Laura Kells, senior archives specialist in the Library’s Manuscript Division, has worked with the Wright Papers extensively and has assisted researchers, including McCullough, in using them. Here Kells answers a few questions about the collection.

An interview of David McCullough from the 2015 National Book Festival follows her responses.

What are the highlights of the Wright Papers?

The papers include their diaries and notebooks, family papers, correspondence files, photographs, scrapbooks, business files and legal papers. The key documents in the story of the invention of the airplane and the development of aviation have been digitized and are available online. Some of the most significant are: The pocket-sized diaries and notebooks in which Wilbur and Orville wrote accounts of their flights at Kitty Hawk, North Carolina, and jotted down data, scientific formulas and computations relating to their aeronautical experiments and their work to design, build and pilot their airplane. An exchange of correspondence between the Wrights and their mentor, engineer and aeronautical authority Octave Chanute, in which they discuss the status of the Wrights’ flight experiments and the development of the airplane. Chanute’s letters to the Wrights are among the many letters from aviation pioneers, business associates, friends, famous people and the public in the Wright Papers. The letters that the Wright Brothers sent to Chanute are part of the Octave Chanute Papers, which the Manuscript Division holds. But these letters were digitized and added to the online Wright Papers collection as well. The hundreds of letters that members of the Wright family wrote to one another. They provide a glimpse into this close-knit family and illuminate the personalities of Wilbur; Orville; their sister, Katharine; and their father, Milton. The letters that Wilbur and Orville wrote to their father and sister while they were away conducting flight experiments at Kitty Hawk or making flight demonstrations in Europe and Fort Meyer, Virginia, are filled with details about their activities and their thoughts about what they were doing. Those that Wilbur and Orville sent to each other when they were apart include technical information and provide insights into their partnership.

What interesting insights do the papers convey about the Wrights?

The papers show the incredibly serious and diligent manner in which Wilbur and Orville progressed from the belief that human flight was possible to being the first people in history to prove it. Their scientific experiments and use of formulas and complicated mathematical calculations demonstrate their high level of knowledge and technical skill—even though neither of them graduated from high school. The family correspondence highlights the significant role their sister, Katharine, played in their lives. Files from later years show that both Wilbur and Orville devoted a lot of effort to protecting what they had accomplished. Wilbur focused on lawsuits over patent rights, and Orville had a dispute with the Smithsonian Institution over challenges to the claim that the Wrights invented the first aircraft to achieve powered, sustained flight.

What items, for you, are especially compelling?

One item that I find compelling is a letter that Wilbur wrote to Octave Chanute on May 13, 1900. He began, “For some years I have been afflicted with the belief that flight is possible to man.” In five pages, Wilbur conceptualized the flight problem and explained how he planned to solve it in such a way that Chanute took him seriously and replied with an encouraging letter. I am also fond of a lengthy letter that Orville wrote to Katharine on September 29, 1902, from Kitty Hawk where he and Wilbur were conducting gliding experiments. It is filled with anecdotal details about camp life and humorous accounts of his efforts to smoke out mosquitoes, chase pigs and trap a mouse. I am also struck by Orville Wright’s account from his 1903 diary of the historic first flight on December 17 as well as the other three flights that the brothers made that day. The six-page entry details the events of the day in a matter-of-fact manner. There is no sense of celebration on achieving the brothers’ dream.

What percentage of the papers are available digitally, and how best can researchers access the others?

There are 10,121 items in the digital collection, which brings together material from a number of sources. In addition to the core items from the Wilbur and Orville Wright Papers that are housed in the Manuscript Division, there are also letters from the Wright Brothers that are part of the Octave Chanute Papers and images from the Wrights’ 303 glass-plate photographic negatives in the custody of the Prints and Photographs Division. The original collection of Wright Papers is larger (approximately 32,250 items). The papers that were not digitized include some of the general correspondence, printed matter, genealogical material and the Marvin McFarland File. It contains material relating to the 1953 publication, “The Papers of Wilbur and Orville Wright,” edited by McFarland.

All of the Wilbur and Orville Wright Papers are available for research in the Manuscript Division Reading Room. The Manuscript Division has prepared a finding aid to assist researchers.

At the 2015 Library of Congress National Book Festival, NPR’s Melissa Block interviewed David McCullough about “The Wright Brothers.” Listen here.