Over the course of four extraordinary days in Oxford, TEDGlobal 2009 explored the Substance of Things Not Seen ... When we look around us, there are things we can observe: Buildings. People. Nature. And then there are things that run unseen through our lives. These hidden forces -- social conventions, biological links, cultural frameworks, coded meanings -- are the connective tissue that binds societies together, the engines that propel organizations and individuals forward. When illuminated, they offer vital insights into our relationships with one another and our world. These are some of our questions, as we delve into the world of the unseen: •What is an accomplished life? •Which universe do we live in? •Is life a mathematical equation? •Where does motivation come from? •Who's defining the new geopolitical map? •How can we observe what we can't see? •Can we design the air we breathe? •What's the economic impact of terrorism? •Should we fear faith? •What makes big cities function? •What do top-secret places look like? •What's the true nature of modern crime? •Can a solar-powered plane fly? •What's the power of music? •Can we put biodiversity in a bank? •How does the brain create the mind?