(Note: This program originally aired earlier this year.) The Internet is, of course, bringing massive changes to our lives -- and bringing them rapidly -- but how often do we really consider what these changes mean, or how they will affect us? In the not-too-distant future, for example, no one will remember what life was actually like before the Internet. What does this unavoidable fact mean? What lessons can we draw from it? Our guest on this edition of ST ponders such questions in his new book; our guest is the Canadian journalist and editor Michael Harris, author of "The End of Absence: Reclaiming What We've Lost in a World of Constant Connection." As Harris writes: "Every revolution in communication technology -- from papyrus to the printing press to Twitter -- is as much an opportunity to be drawn away from something as it is to be drawn toward something. And yet, as we embrace a technology's gifts, we usually fail to consider what we're giving up in the process. Why would we bother to register the end of solitude, of ignorance, of lack? Why would we care that an absence had disappeared?" This is an engaging and accessible book about why such realities as "absence" and "solitude" should matter to us as a culture -- and as individuals. In a world where (for better or worse) "being online" draws ever closer to being synonymous with "being alive," this book does seem like an important and timely one.