Most of us are only too aware that, whatever roles we have in today's fast-moving world, much of our success lies in getting others to say 'Yes' to our requests. What many people might not be aware of, though, is the vast amount of research that has been conducted on the influence process. What factors cause one person to say 'Yes' to the request of another? "Yes!" is full of practical tips based on recent academic research that shows how the psychology of persuasion can provide valuable insights for anyone interested in improving their ability to persuade others - whether in the workplace, at home or even on the internet. It combines the counter-intuition of Freakonomics with the popularizing of "Does Anything Eats Wasps?" For each mini-chapter contains a mystery which is solved in a way that provides food for thought for anyone looking to be more persuasive, and for anyone interested in how the world works.