Why are we more likely to forgo the opportunity to sell a e100 bottle of wine rather than actually taking money out our wallet to pay for it, when ultimately the 'opportunity cost' of doing so is the same? Why would the 'endowment effect' mean that we value a free ticket worth hundreds of pounds more than the money we would get from selling it? As the most vivacious and vociferous founding member of behavioural economics, Thaler presents his insightful findings with stories about data and experiments and shows us how to avoid making costly mistakes in our own lives.