And yet, long before neural implants, the iPad and the talking phone, there was the book. It, too, was described as a living, breathing entity intimately connected with our own. With its hard cover and soft, hidden interior, the book in many ways resembles the human body — and the mind. It contains secrets, waiting to be uncovered. We open a book, or, rather, it “opens up” to us, not unlike the friend who responds to our sympathetic probing. Our tendency to anthropomorphize the book’s features (we speak of its spine, headers, footnotes, etc.) emphasizes the connections between us. When we “face” the book, our own spine curved over its, our mind engrossed in a borrowed consciousness, we have the vague sense we are interacting with something that, while not exactly human, is uncannily similar to ourselves.

Perhaps this is why, for all their innovation, the Kindle, Nook and iPad cling to the form of the traditional book, from their size to their covers to the technology they use for page turning, replicating that familiar intimacy. We don’t want to give up our experience of reading as an “opening” into another mind, as a progressive exploration, registered in the turning of pages, of thoughts that originated elsewhere.

After all, the relationship between human reader and “animated” book has been forged over centuries. The Bible, perhaps the first book to be characterized in these terms, was thought to be the material embodiment of Jesus Christ, “a living and breathing likeness of Him” in the words of Erasmus. Since Christ was understood to be the carnal manifestation of the Scriptures — the Word made flesh, according to the literary scholar James Kearney — the Bible was reflexively endowed with human properties. “The leaves of this booke be the armes, the handes, legges and feete” of Christ, said Bishop John Fisher in an early-16th-century sermon. The capital letters dyed in red are “the great wounds of his body, in his handes, and in his feete, and in his side.”

These kinds of descriptions quickly spread to more secular books. Books, said the 17th-century Welsh physician and metaphysical poet Henry Vaughan, are “full of blood . . . ev’ry line a vein.” The 19th-century British scholar Henry Bradshaw classified his books, “living organisms,” in terms of genre and species. Coleridge called the library “a living world, and every book a man, absolute flesh and blood”; and Emily Dickinson asked whether her verse was “alive,” and if it “breathed.”

A widespread perception held that the book was animated from within by its author. “There is a man who writes,” said the British Rev. Frederick Denison Maurice in 1856, “and when you get acquainted with that man you get acquainted with the book.” While this was a longstanding assumption about reading, it gained particular influence during the Industrial Revolution, when more books were in circulation and “acquaintanceships” made through reading could substitute for a diminishing real-life community. The metaphor of the “book as friend,” as the historian Ronald Zboray puts it, arose to ward off the loneliness of modern existence. Books are “living friends,” Bronson Alcott, Louisa May Alcott’s father and a noted philosopher and educator, wrote, and added, “The more life embodied in the book, the more companionable.”

Alcott and his contemporaries regarded the book as a container for consciousness, a way to access the innermost part of another human being, otherwise unreachable. For this reason, it was believed to be an especially effective way to communicate with the deceased. The 18th-century Scottish poet James Thomson claimed that to read was to “converse with the mighty dead.” And in the 19th century, the influential American preacher Edwin Hubbell Chapin described books as “the embodiments and manifestations of departed minds — the living organs through which those who are dead yet speak to us.” At a moment when spiritualism was surging in America, reading, it was suggested, could help people establish contact with the deceased through the “medium” of the book.

Today we have online resources like Legacy Locker and SecureSafe that allow mourners to grieve for loved ones through their digital remains. But the book was the earliest technology connecting the living and the dead, a way of tapping into the thoughts or experience of those who are no longer physically present.

One could argue that all media, whether a painting, a film, an installation or a book, invite us to immerse ourselves in the unfamiliar contours of another’s mind. And yet, the book is singular in this regard. “Of all the inanimate objects, of all men’s creations, books are the nearest to us, for they contain our very thought, our ambitions, our indignations, our illusions,” Joseph Conrad wrote in 1905. Conrad was echoing Thoreau, who, some 50 years earlier, wrote that the book “is the work of art nearest to life itself. It may be translated into every language, and not only be read but actually breathed from all human lips; — not be represented on canvas or in marble only, but be carved out of the breath of life itself.” Part of the appeal of the book, then, is the way it enters our bodies and our souls, forcing us to reimagine ourselves in light of its transformative influence. “The symbol of an ancient man’s thought becomes a modern man’s speech,” as Thoreau put it, suggesting that in reading, we are actually, physically incorporating the dead into the living.

Digital alarmists predict that soon we won’t be reading books at all; they will simply be implanted in our brains. But books have been in there for a long time. The 19th-century theologian Noah Porter claimed that the books people read “enter into the structure of their being” and are “assimilated into the very substance of their living selves.” Nothing pleases us more than to peruse the shelves of books read in our youth and to recognize aspects of our identities lodged there. “So many have cleaved to their libraries with so fond an affection,” Porter writes, “and have learned to conceive of them as parts of themselves, as in a sense visible and tangible embodiments of their own being.”

Perhaps these days our iPhones and MP3 players and even our Nooks, rather than our printed books, are parts of ourselves, the lifelike objects without which we feel lost and disoriented, and even, somehow, less alive. But the book was there first, blurring the boundaries between human and nonhuman, between our bodies and the outside world. We are not so much entering a brave new universe as continuing an established tradition. Sure you could say our media technologies, starting with the book, have tended to sequester us in cubicles, but they have also been, and continue to be, among the most cherished company we keep.

Gillian Silverman is an associate professor of English at the University of Colorado Denver and the author of “Bodies and Books: Reading and the Fantasy of Communion in 19th-Century America.”