Still, hope springs eternal, and many of us pack our books away, filling spare rooms with bookshelves and attics with old titles. Those books hold what our minds cannot, and we hope that having read them once, we will be able to quickly rediscover their secrets if and when the need arises. To help us in this quest, we have margins. It is here that most of us make our stand against time’s inevitable fade to black. Notes, exclamation points, stars, doodles, complicated systems of acronyms and symbols—all serve as maps to intellectual lands we once traversed and may someday revisit. But they are spotty guides. Sometimes, the directions are illegible. Other times, we find that we forgot to mark a particular road or byway because we didn’t realize it was important. And without any real way of pinpointing our position, the search through this hazy mess of chicken scratch can be only marginally more efficient than rereading the book itself.

Compared to this, electronic text is a GPS system. You tell it where you want to go, it finds the route. The whole book is searchable. So, for that matter, are your notes, which can all be stored. Favored passages can be clipped and saved in a separate file to facilitate more rapid review. When text ceases to be fixed, when margins swell to an infinite expanse, when every word can be sorted and searched, the failings of our brains are hardly noticeable. Your bookshelf becomes your mind’s external hard drive. It’s a shiny new e-brain, a Google that searches your personal intellectual universe.

The point was driven home to me while reading William Powers’s brilliant essay “Hamlet’s BlackBerry: Why Paper Is Eternal,” which considers the evolution of paper and the way it has subtly shaped not only the way we read, but what we read. “The persistence of paper flies in the face of a widely held popular assumption about technology,” Powers writes, “propagated over the years by breathless futurists and science-fiction writers.” True enough. But it was at about that moment that I realized I was reading “Why Paper Is Eternal” paperlessly, on my computer. I had downloaded it for free, which could be done because there were no shipping or production costs associated with the electronic file, and I decided to read it in my PDF viewer (the wonderful freeware Skim, for those who are interested) so I’d be better able to jot down thoughts and pull quotes. Paper may be eternal, but for some purposes, it’s simply inferior.

Let me be clear: though the Kindle has some advantages over traditional books, for the moment, I’d stick with the low-tech option. The problem is that the Kindle tries to compete too directly with paper. It attempts to electronically mimic the experience of reading a book. But the book is very, very good at providing the experience of reading a book. In this way, the Kindle occasionally comes off as if Ford, failing to make the conceptual leap to the car, had instead built a motorized horse. Sure, there would be some advantages: the robo-steed would never grow tired, and could be outfitted with more plush seating. But horses are pretty good at being horses. And books, like horses, have evolved to maximize their advantages.

The true promise of the Kindle, and its inevitable descendants, is in creating a product that goes where the book cannot. Printed text is fundamentally limited. Once on the page, nothing more can be done with it. With digital text, everything is a draft, to be edited, altered, broadened, remixed, and redirected. As better conveyors of electronic text are developed, the big question is how content itself will change to take advantage of the new opportunities.

Ezra Klein is an associate editor at The American Prospect.