This is well worth reading, in view of the scarcity of decent information on this topic. Firstly, she writes in a beautifully clear style, and she has experience of treating dissociation.
I found several problems. She spends lot of time talking about multiple personality disorder, which may be an exciting topic but in terms of number of sufferers, other forms of identity disorder deserve more space. Secondly, a lot of her work seems to be guided imagery. Do we have any evidence for how good this is. She also mentions other forms of treatment including Reiki. Do these really work? It might have helped if she included the voices of the sufferers, and what happened to them during treatment.
For people suffering from Dissociative Disorder, there isnt a lot to help them, so this is a start.