[W]riting [a book] is an excruciating process full of failure. But when a book succeeds, even partially, it represents a level of concentration and refinement—a mastery of subject and style strengthened through patience and clarified in revision—that cannot be equaled. Writing a book is an extraordinarily disproportionate act: What can be consumed in a matter of hours takes years to bring to fruition. That is its virtue. And the rare patience a book still demands of a reader—those precious slow hours of deep focus—is also a virtue.