Bringing together the latest insights from psychiatry, psychology, and philosophy, Daniel Nettle sheds light on happiness, the most basic of human desires. Nettle examines whether people are basically happy or unhappy, whether success can make us happy, what sort of remedies to unhappiness work, why some people are happier than others, and much more. The book is packed with fascinating observations. We discover the evolutionary reason why negative thoughts are more powerful than positive ones. We read that happiness varies from country to country, for example, the Swiss are much more happy than Bulgarians. And we learn that, in a poll among people aged 42 years old--peak mid-life crisis time--more than half rated their happiness an 8, 9, or 10 out of 10, and 90% rated it above 5. Nettle, a psychologist, is particularly insightful in discussing the brain systems underlying emotions and moods, ranging from serotonin, to mood enhancing drugs such as D-fenfluramine, which reduces negative thinking in less than an hour; to the part of the brain that, when electrically stimulated, provides feelings of benevolent calm and even euphoria. In the end, Nettle suggests that we would all probably be happier by trading income or material goods for time with people or hobbies, though most people do not do so. Happiness offers a remarkable portrait of the feeling that poets, politicians, and philosophers all agree truly makes the world go round.