SAN FRANCISCO - Among the many pleasures of a nationwide book tour is the privilege of seeing America through the lens of its best impulse. I have been in cities on both coasts, north to Chicago and south to Washington, D.C. In each place I am ushered into the realm of another age, yet a peculiarly contemporary one.
To publish and promote a book - mine is ''Constantine's Sword, the Church and the Jews: A History'' - is analogous to conducting a political campaign, but instead of encountering citizens as interest groups or voting blocs, one meets the people as book sellers, book buyers - readers.
At a time when so much of society seems organized around the technologies of the flickering screen or the now ubiquitous cellphone, it seems a miracle that the relatively primitive object of the book should not only be surviving but thriving.
Bookstores are bustling, lively places. Large and small, in cities and suburbs, at night or in mid-morning, they are a joy to enter, with staff who actually seem to love what they do; with stock displayed to excite the gaze; with customers entirely unlike customers in other kinds of stores.
In supermarkets or clothing shops, we are hunters and gatherers, fierce in acquisition. But in bookstores, we are browsers, consciously at the mercy of a curiosity that overrides programs, schedules, and even the narrow purpose that brought us here. In other stores, we are alert to what is around us, but in bookstores we must be equally attuned to what is going on inside our own hearts and minds.
This is so, of course, because reading is an act of interiority pure and simple. Its object is not the mere consumption of information or sensation, nor is the encounter that matters most the one with the author of what is read.
Rather, reading is the occasion of the encounter with the self. The creativity of the writer comes into its own only as the source of a reader's quickened intellect, with thought moving toward contemplation, impression toward awareness.
It is the hope of arriving at this state of chosen inwardness that brings people into bookstores. What makes bookstores places of a rare, if implicit, communion is that everyone in them wants the same thing, whether they peruse shelves marked Dostoyevsky or Dickens or Didion.
Bookstores are a refuge from the plague of distraction and banality that mark so much of contemporary life. I have, for example, never seen anyone on a cellphone in a bookstore. Thus, reading, a supremely solitary act, is oddly the occasion here of a precious solidarity. Customers move carefully past each other, brooding over pages in their separate aisles, but absolutely conscious of not being alone in this way of being human.
That quiet communion is also part of what brings us into bookstores, and it explains why bookstores thrive even in this era of Amazon.com.
No wonder the people who work in bookstores seem a breed apart. Obviously, they are likely to be readers themselves. They are business people too, of course, but as such they prove, against much of what we see in markets, that commerce and meaning are not incompatible.
Their version of being helpful to a customer is like matchmaking, aiming for the marriage of minds, which is why a writer's heaven is on the list called ''Staff Recommends.'' Yet every book is an object of reverence, and the range of titles invites even the vainest of us authors to let go of feelings of competitiveness and envy. Writers, too, can be at peace for once.
The bookstore is a sanctuary of the idea that truth is all around us, if always just beyond. The categories into which it is broken down for display - history, fiction, fantasy, science, poetry - are like markers by which to measure the expansiveness of human expression. And expression - here is what bookstores reveal and promise - is what saves us.
This is a big country. This is a free country. Our talk of politics is how we find a way to think of ourselves as one, even if such talk feeds on what divides us.
I began this reflection by comparing a book tour to an election campaign, but here is a difference: Politics thrives on a sense of what is wrong with this nation, but a broad swing through these enchanted islands of the word emphatically demonstrates what is right.
The book is the best thing human beings have done yet, and in the booming bookstores of America it has found an accidental shrine.