As you sit there, you perceive things in a certain way and assume all of it is real. You mentioned integration. Only when multiplicity starts interfering with a system's ability to function in daily life does it become a 'disorder'. If there weren't many of us, we would most likely be dead by now, by our own hand or that of one of our abusers.
Cooperation is another major option that multiples can choose before or instead of integration.
However, we feel that this book gives systems some good ideas and is a decent starting point. There are some excellent books in print that have primarily the same intent, but appear to approach the subject better. It is a valuable article for 'singletons' to read too. Our system has chosen the cooperation path, and we feel very strongly that this is the best path for us. We are supportive of those systems who make the informed decision to integrate.