I love the Positive Discipline series and this book was no exception. However, there were a few things that gave me pause and made me rate it as a 4-star book instead of a 5-star book.
First and most importantly, the authors advocate letting children as young as 3 months old cry it out to go to sleep at night. In my opinion (and several recent studies have started to demonstrate this), leaving a baby (especially one who cannot yet understand a verbal explanation) to cry alone in the dark is NOT a positive discipline method; instead, it teaches her that her parents will abandon her when she is frightened, hungry, or otherwise in need of comfort. To me, the authors' infant CIO agenda is in direct conflict with the rest of the book, where they encourage parents to build a relationship of mutual respect and trust with their children.
Secondly, they support their CIO argument with a statement that babies 3 months and older never need to eat at night. While it may be true that some percentage (and maybe even a majority) are ready to night wean by 3 months, that is in no way true for all babies. I'm thinking in particular of preemies and babies with growth problems, but in my experience, a large percentage of infants genuinely aren't ready to stop eating at night until they're a little bit older. I wish the authors would have encouraged the reader to check with his or her pediatrician on this point, instead of making a blanket statement with the potential to be genuinely dangerous.
Finally, the authors' own strange beliefs come seeping through as "parenting advice" at times. Telling me that I must require my children to use headsets when speaking on cell phones so that they don't develop brain tumors is medical advice, not parenting advice (and not particularly evidence-based medical advice, at that). I wish they would have stuck with doling out parenting advice.
All of that said, these are minor flaws in what is otherwise a very helpful guide to dealing with common childhood discipline problems in a way that's kind, firm, and respectful of the parent-child relationship. I would definitely recommend this book to other parents interested in alternatives to punishment-based parenting.