This book came out when my son had just turned 3. I had been tearing out my hair worrying about potty training, and I believe that if I'd had this book when I was first considering the issue, I'd have had a much easier time of it. The book is short and easy to read, but dense with useful information. Brazelton backs up his "method" with firsthand information about child development. He is a doctor who has seen many children and their parents, not some person who got lucky with a forceful method that they think should work for everyone.
Brazelton stresses that age is not a determinant for potty training readiness. He outlines several readiness signs. If you've researched potty training, most will seem familiar to you. What I found unique about his list is that he indicates that ALL conditions must be met before a child is ready, so there is no guesswork.
Brazelton's "method" isn't a step by step troubleshooting guide. I kept wishing for such a thing, but it doesn't exist because parents need to use judgement and compassion in helping a child achieve this milestone. There is no sure fire recipe. But there are some things you can do that are key: Don't force a child who isn't ready. Don't approach potty training as a discipline issue. Do give children choices. Do remove barriers such as training then while bare bottomed so that they don't need your help with clothing. Don't show your anxiety about training or the child will pick up on it.
The book includes chapters on special situations (constipation, encopresis, etc.). It also gives gender specific advice such as waiting to teach boys to urinate while standing until they are proficient at going "Number 2" in the toilet (once they stand up, it's hard to get them sitting again). I highly recommend this book and would suggest that even parents with children as young as 1 read it to prepare for potty training. Plan on spending at least a few weeks on making the transition, and more realistically, months. My son was 3 years and 3 months before we made any real progress at potty training.
This is NOT the book for anyone who thinks children should train by an arbitrary age. It is NOT for anyone who judges a parent based on when their children learn to use the toilet. It is DEFINITELY NOT for anyone who wants overnight success.