This book, "The Power of Habit" by Charles Duhigg, explores the science of habit formation and change at individual, organizational, and societal levels. It argues that habits can be changed if we understand how they work.

Part One focuses on individual habits and introduces the habit loop: cue, routine, and reward. The book explains the neurology of habit formation, citing the case of Eugene Pauly (E.P.), who, despite severe memory loss, retained habitual behaviors. It highlights the role of craving in driving habits, using the example of Pepsodent's success, which was partly attributed to the tingling sensation it created, leading to an anticipated fresh feeling (reward). The story of Lisa Allen, who overcame smoking, drinking, and obesity after a surgery, is presented as an example of habit change. The Golden Rule of Habit Change is introduced, suggesting that to change a habit, one must keep the cue and reward but swap the routine. The book also discusses how new habits are created.

Part Two examines the habits of successful organizations. It introduces the concept of keystone habits, like worker safety at Alcoa under Paul O’Neill, which, when addressed, can create a ripple effect, changing other organizational habits and significantly improving the company's performance and profits. The success of Starbucks is attributed to their training programs that teach employees self-discipline and willpower through habit loops, such as the LATTE method for dealing with unhappy customers. The book explores how leaders can leverage crises to create new habits within organizations, citing the King’s Cross station fire and the subsequent safety reforms in the London Underground, as well as changes at Rhode Island Hospital following medical errors. It also delves into how companies like Target analyze consumer data to predict (and manipulate) habits, even identifying pregnancies, and how Procter & Gamble turned Febreze into a billion-dollar business by understanding and tapping into consumers' habitual desires for a rewarding scent after cleaning. The initial failure of Febreze highlights the importance of identifying the correct craving (a pleasant smell after cleaning, not just scentlessness).

Part Three investigates the habits of societies. It recounts how the Montgomery Bus Boycott and the civil rights movement succeeded, in part, by changing ingrained social habits. The story of Rick Warren and the building of Saddleback Church illustrates how appealing to people's social habits can create large-scale movements. The final chapter explores the neurology of free will, raising ethical questions about responsibility for our habits, referencing the ideas of William James and the case of a man who killed his wife during a night terror.

The Appendix provides a Reader’s Guide to Using These Ideas, offering practical advice on how to identify the habit loop in personal habits and experiment with new routines to change unwanted behaviors, using the example of a chocolate chip cookie habit. The book emphasizes that while there isn't one formula for changing all habits, understanding the cue, routine, and reward provides a framework for intervention.