To be brilliant, you have to be irrational! Why is Red Bull so popular - even though everyone hates the taste? Why do countdown boards on platforms take away the pain of train delays? And why do we prefer stripy toothpaste? We think we are rational creatures. Economics and business rely on the assumption that we make logical decisions based on evidence. But we aren't, and we don't. In many crucial areas of our lives, reason plays a vanishingly small part. Instead we are driven by unconscious desires, which is why placebos are so powerful. We are drawn to the beautiful, the extravagant and the absurd - from lavish wedding invitations to tiny bottles of the latest fragrance. So if you want to influence people's choices you have to bypass reason. The best ideas don't make rational sense: they make you feel more than they make you think. Rory Sutherland is the Ogilvy advertising legend whose TED Talks have been viewed nearly 7 million times. In his first book he blends cutting-edge behavioural science, jaw-dropping stories and a touch of branding magic, on his mission to turn us all into idea alchemists.