This is a very smart book, full of practical advice and many examples of real people successfully having more than one partner at the same time. Low on flowery rhetoric, and full of practical, real-world case stories of complex lives and relationships. She works as a counselor, and it shows.
The book is very low on, "This is what I think, and/or what poly theory says", and very high on, "Here are relationships I've seen work (and not work!) in the real world".
She immediately deals with emotions like jealousy, envy, insecurity and compulsive behavior, inevitable in any relationship, but more so in polyamory. She's very practical and matter-of-fact, and provides useful models to develop relationship skills. She's skilled, thoughtful and wise. I read the book in a single evening, unable to put it down.
If you are contemplating polyamory, this is a must-read. I would also recommend a therapist experienced in polyamory, if at all possible. It's a step that shouldn't be taken lightly.