What is a book? This is a question we will want to answer if we want to enable books to reflect the electronic age and not the ink-on-paper era, just as Gutenberg and his heirs fully exploited that once-new technology back when, well, the ink was still fresh.
I don't think a precise definition is possible, certainly not one that will clearly and unambiguously delimit books, journals, magazines, newspapers, and any other print media, and also add electronically without claiming blogs, RSS feeds, wikis, mail-lists, and website forums. Each of these are distinct entities.
Some clear examples of ' What is a book?