Science and technology force us to ask some of the most challenging and unprecedented ethical questions in the world today. These issues encompass what it means to be human, how we relate to others and our world, and how we find meaning in life. How we can find a shared ethics for an interdependent world? In her 2006 CBC Massey Lectures, ethicist and McGill University professor Margaret Somerville tackles some of the most contentious issues of our times, and proposes a brilliant new kind of ethical language and thought to help us navigate them.