And the tone of this book is warm, upbeat and optimistic, encouraging us not to give up or to deny the evidence all around us, but to embrace the part we can play in being a force for good.

If you think we are all too insignificant, too small to make a difference, they point us to a stonemason working on Europe's medieval cathedrals. "He could have chosen to throw down his tools because he was not going to personally finish the entire cathedral. Instead, he worked patiently and carefully on his one piece, knowing he was part of a collective endeavour that would lift the hearts and minds of generations. That is optimism, and cultivating it will not only be a crucial step to advancing our human story, it will also improve your life today."

We are not powerless. It is not too late. With examples from the past, as well as ideas for the future, this book is energising, hopeful and positive.