The Future: What Books Will Become
A book is a self-contained story, argument, or body of knowledge that takes more than an hour to read. A book is complete in the sense that it contains its own beginning, middle, and end.
In the past a book was defined as anything printed between two covers. A list of telephone numbers was called a book, even though it had no logical beginning, middle, or end. A pile of blank pages bound with a spine was called a sketchbook. It was unabashedly empty, but it did have two covers, and was thus called a book.