Books, at least the physical kind, have sentimental value. You can lend a well-worn copy to a friend or inscribe a special message inside one as a gift. This essay by Anne Fadiman, which appeared in her book of essays, Ex Libris: Confessions of a Common Reader, illustrates the symbolic meaning of physical books on a bookshelf and what those books meant to her and her husband.
An excerpt from the essay Marrying Libraries.
Fadiman, Anne. "Marrying Libraries," Ex Libris: Confessions of a Common Reader. 1998.