If you want to compare them to printed books, count the number of words and divide by 600, which gives you the approximate number of pages assuming a normal page layout and typeface, or 700 for a densly printed book. I just checked and Inevitable is about 480k words, so would be about an 800 page book given a normal paperback layout. So you've still got some way to go to reach the Tom Clancy sort of supersized book.