Celebrating books and reading helps us rediscover something fundamental about ourselves as Americans.

Ours is the only world civilization whose basic institutions were formed entirely in the age of print. Our independence was declared and our Constitution adopted in printed formats; open access to knowledge by our people has been the key to our development as a more inclusive and dynamic democracy.

Thomas Jefferson said he could not live a day without book. His amazing library, from which the Library of Congress developed, was divided into three categories: memory, reason and imagination.

Books are guardians of memory; they take each of us into the stories and trains of thought of other times, places and people. Whenever we of an older generation read to the young, we are helping them discover that mute voices from the past can be better guides for the future than talking heads in the present.

Reason is the great referee in the game of life. It is the essential, invisible force that has enabled Americans to sustain deep individual convictions while learning to tolerate — and even be enriched by — the very different beliefs and customs of others.

Books convince; they do not coerce. In libraries throughout America, books that disagree with each other stand peacefully next to one another in the stacks, and readers work peacefully alongside each other in reading rooms.

Books open up for us the royal road of imagination. They take us out of our hurry-up, present-minded, noisy world into what John Keats called “silence and slow time,” where our thoughts are not defined by someone else’s stream of images on a television or computer screen or sounds on a music player.

My predecessor as librarian of Congress, Daniel Boorstin, said that books uniquely help us to form the previously unimagined question and to accept the often unwelcome answer.

Saturday marked the 10th anniversary of the National Book Festival. Why, you may ask, celebrate books at a time when everything is going digital? Certainly the book business is in a transitional state like all print media.

But books are not going away. New technologies tend to supplement rather than supplant older ones. Television did not destroy radio; the VCR and DVD players did not keep people from movie theaters.

While the technologies we use to read books may change, the value of reading them does not; and the values of the book culture that helped create our nation must not be left behind.

In an era of 140-character messages and the increasing destruction of the basic unit of civilized discourse (the sentence), it is critical that we continue to encourage the production and reading of books.

Both electronic and analog media will have their place in the future of reading and research. Electronic books offer the ability to pinpoint a word or phrase in seconds, and there is a tsunami of information and much new knowledge on the Internet.

Yet book publishing has increased about 40 percent globally in the past decade, and no less a technology advocate than Bill Gates has said that “reading off the screen is still vastly inferior to reading off of paper. … when I am reading something over about four or five pages, I print it out so I can carry it around with me and annotate for my own purposes. And it’s quite a hurdle for technology to achieve, to match that level of usability.”

Throughout its 210-year history, the Library of Congress has collected books in more than 450 languages and in almost all areas of human endeavor. This more permanent and tamper-free record of human knowledge and creativity must be preserved in its original form, even if more and more of it becomes available digitally.

Millions of users visit our Web site (www.loc.gov/memory), which provides free access to nearly 16 million original documents of American history and culture from the library’s unique treasures.

We have opened another popular (and also free) site in seven languages: the World Digital Library (www.wdl.org), with the sponsorship of the United Nations Educational, Scientific and Cultural Organization (UNESCO) and collaborative help from 105 of the world’s great cultural institutions. Rare books, manuscripts, maps and other primary sources help tell the stories and highlight important contributions to humanity of all countries.

The main purpose of our growing presence online is to provide, through new technology, high-quality content that can stimulate people everywhere to form their own questions that will motivate them to seek out answers for themselves in the stored wisdom of books.

This weekend’s festival offered attendees the opportunity to listen to and talk with stellar writers and illustrators and experience an enjoyable supplement to the adventure of reading.