This is a disappointing and not very useful book. First, Duhigg sets us up with his introduction about how super-productive people like Atul Gawande are and promises that he'll deliver their secrets. The book is full of anecdotes and their relation to research. There's little to no summarizing with the steps a person should take to be smarter, faster, and better. As a reference book, it's useless because you have to wade through hundreds of pages of text to find any nuggets.
The clincher for me was when I got to the end and read his appendix. This was where he was supposed to tell us how he put the lessons of the book into practice as he wrote the book. It's where he was supposed to tell us how we all can manage the load of commitments we have to be as productive as Gawande, a best-selling author, a well-known surgeon, a Harvard faculty member, an advisor to the World Health Organization...
But it never happened. Instead of finding out how Duhigg managed the responsibilities of work, family, and personal needs, we found out how he organized and managed to write the book. Nope. As far as I know, his family life fell apart and his co-workers hate him for shirking his duties.
In short, this book could have been much better in many ways. Don't waste your money or your time.