Is my experience real? Or just a movie in my head? Am I no more than a super computer? You are your brain, neuroscientists tell us. Everything happens in there. Yet even the most sophisticated brain scan cannot tell us who we are. Nothing in our neurons remotely suggests the rich nature of our experience, the colours, sounds and smells that make up our lives. When Tim Parks came across a radical new theory of consciousness, he set on a quest that moves through one sparkling encounter after another to arrive at the deepest of questions: what stuff exactly is consciousness made of? And where is it? Inside or out?