I never read the book and it's been a while since I've heard people talk about it but my understanding is that basically whenever you are not directly interacting with the puppy he should be crated. I think the general purpose is to have a dog who believes all good things come from you, not from the environment. I think it's designed more for people who plan to do sports/competitions rather than average pet owners. Most people feel it's too strict, and honestly for most pet dogs they would end up spending a ridiculous amount of time in their crate. I feel like only people whose life really revolves around that puppy would be able to do this in a fair way. I don't know of anyone who has done it.