Good Morning, CassyO~
I love the book, and think it's worthwhile to read on one's own. It's meant to be used by clients as well as therapists.
It has helped me stay focused with it, to work out of it in a group, but that's not to say you wouldn't benefit immensely from using the skills in it. Some seem fundamental, but they are not to be dismissed.

Does your therapist work with others' who struggle with DID? Perhaps it would be worth dropping a hint for him to read this book and work with you and other's from it.

I hope for you!