We need to spend as much time rethinking as we do thinking. Why do we refresh our wardrobes every year, renovate our kitchens every decade, but never update our beliefs and our views? Why do we laugh at people using computers that are ten years old, but yet still cling to opinions we formed ten years ago? For too many of us, our ways of thinking become habits that we don't bother to question, and mental laziness leads us to prefer the ease of old routines to the difficulty of new ones. We fail to update the beliefs we formed in the past for the challenges we face in the present. But in a rapidly changing world, we need to spend as much time rethinking as we do thinking. Think Again is a book about the benefit of doubt, and about how we can get better at embracing the unknown and the joy of being wrong. Evidence has shown that creative geniuses are not attached to one identity, but constantly willing to rethink their stances and that leaders who admit they don't know something and seek critical feedback lead more productive and innovative teams. New evidence shows us that as a mindset and a skilllset, rethinking can be taught and Grant explains how to develop the necessary qualities to do it. Section 1 explores why we struggle to think again and how we can learn to do it as individuals, arguing that 'grit' alone can actually be counterproductive. Section 2 discusses how we can help others think again through learning about 'argument literacy'. And the final section 3 looks at how schools, businesses and governments fall short in building cultures that encourage rethinking. In the end, learning to rethink may be the secret skill to give you the edge in a world changing faster than ever.