Wealthy people don't just have better toys; they have better nutrition and better medical care, more free time and more meaningful labour-more of just about every ingredient in the recipe for a happy life. And yet research consistently shows that they aren't much happier than those who have less. If money can buy happiness, then why doesn't it? The authors argue that five principles apply to the money/happiness equation, including 'buy experiences instead of things' and 'help others instead of yourself'. In the end, they show that money can buy many of the things that make us happy; and if it doesn't, the fault is ours.

Only recently have we been able to apply science to one of the world's oldest questions: "What is the nature of happiness?" In this edited interview, the author of the 2006 best seller Stumbling on Happiness surveys the field. Gilbert explores the sudden emergence of happiness as a discipline, reviews the major findings (including the mistakes we all make in predicting how happy or miserable we'll be), and examines the role of happiness in productivity on the job. He describes what makes us truly happy--it's not a promotion or a new house--and sketches out a "happiness diet" that emphasizes small, routine efforts. Looking forward, Gilbert discusses the breakthrough work of his colleague Matthew Killingsworth, whose iPhone-enabled real-time surveys of people's moods are providing an ultra-high-resolution picture of how our emotional states shift from minute to minute. A sidebar by Killingsworth offers a preliminary look at his findings and their implications for our personal and workplace lives.