I haven't read that one, but another commenter on this story told me that they hate that book - in part because the guy who wrote it was apparently abusive in many of his relationships, and also because it has a lot of rules about what is "real" polyamory, such as being friendly with your metamours (your husband's partners), having no hierarchy in your relationships, e.g., your marriage is no more important than a relationships with anyone else. But as I said, I haven't read that one, so I don't know first hand.

My very favorite is Opening Up because it asks a lot of questions that help you come to understand what you want your ENM relationships to be like, rather than giving you a bunch of rules about what it should be like (beyond honest, communicative, self-responsible). There are lots of different styles of poly and they are all valid. Relationship Anarchy (which is how More Than Two leans, I believe, based on the other person's comments) is only one style.

Hope that helps.