I gave this 3 stars instead of 4 because it's really a minor work, covering a small subject with appropriate focus and pace. Most of the cognition/neuroscience/self-help/business books out there (is there any other genre of non-fiction these days?) try to cram in too much, and the worst end up an incoherent mess. (I'm thinking of Imagine in particular.) The Power of Habit avoids those pitfalls and deserves high praise for doing so, but that doesn't make its topic the key to all human existence, just one curious corner of it.What it boils down to—and Duhigg takes nearly 300 pages to develop this in appropriate detail—are two points. One, habits are cycles of Cue - Routine - Reward, and they are powered by our Craving for that Reward. (I'm using capitals to distinguish ideas that Duhigg explains and gives many examples of in the book.) Two, to change a habit, you can't change the Cue or the Reward: you have to change the Routine (which is presumably, if you're trying to change, the Bad Thing you want to stop doing). The trick is identifying exactly what the Reward is deep down, not just on the surface, and thus finding alternate Routines to satisfy your Craving.The examples pull from the standard stock of Gladwell, Lehrer, and That Whole Sick Crew: we get the latest installment of the adventures of America's favorite superheroes, Procter & Gamble, this time the Legend of Febreeze rather than the Story of Swiffer. (We're spared How 3M Got Its Post-Its.) But Duhigg doesn't assume that the only purpose of understanding how our minds work is to improve our business results, so we get Rosa Parks again (last seen in Quiet), but in a chapter on "social habits," i.e. the civil rights movement. (Duhigg skips over other, more controversial social habits: religion, racism, sexism, etc.) In a refreshing change, he pulls out in an appendix "A Reader's Guide to Using These Ideas"—not quite coming directly clean on the book's role as self-help, but getting very close.That self-help content boils down to:1) Identify the Routine (i.e. what you think of as the habit, the part you want to change)2) Experiment with Rewards (figure out exactly what Craving is powering the habit)3) Isolate the Cue4) Have a Plan (i.e. come up with a new Routine)... which is pretty basic stuff.So why is this a satisfying read, exactly? Well, because it (for once) provides evidence and explanation for something you actually do with your own mind, something you can absolutely identify with as a reader. If that kind of old-school restrained ambition makes it a minor work, so be it. The world needs more minor works.