This book was awesome. In recent years, there has been a lot of research on willpower. What is willpower? Can it be depleted? Can it be developed? If it can be developed, then how? The authors answer all of these questions while citing numerous scientific studies. One of the coauthors is a scientist while the other is a New York Times science journalist, and that’s a great mix for a book like this.

In practical terms, it seems like people have an exhaustible supply of willpower, and that everything taps into the same supply — that is, rather than having willpower for dieting and willpower for not biting your nails and willpower for not smoking, you have willpower for “everything” which can be used up when you’re trying not to eat or to bite or to smoke. Furthermore, willpower is exhaustible, meaning that you only have so much of it during the day. If you use some for not eating candy from the bowl next to you, then you might not have any left when someone offers you a cigarette an hour later. This is the bad news. The good news is two-fold: that willpower can be strengethened, just like a muscle, and that there are hacks that let you accomplish what you want without tapping into your limited supply. The book is very practical.