I have done this in the past. I does take some hand strenght so this is how it's done. From the open end of the book grip the book with 2 hands, thumbs on top, fingures on the bottom and the binder at your belly. With your grip loose fold the book in a V shape. Now tighten your grip big time. Now try to get the V to lay flat without the pages slipping between each other. You might want to use your knee to start the pages riping. Once all the pages have ripped back a few inches change your hand motion from both down over your knee to left hand up and right hand down and rip the rest of the book. I have found that a 4 inch thick book is just as easy as anything thinner. OK, I just ripped my phone book in half but I found the grain to be parellel to the binder on this book. I tried the above method and It wouldn't rip. So not all books have the grain in the same direction. The guide above is the way, you just have to find the grain direction.
