We often assume that we can’t fix the big problems we see in the world around us. And that trying is for suckers - who’ll just end up sad, exhausted and defeated. 

Dr Laurie Santos and Dr Jamil Zaki meet people who have tried to make a difference in their communities - often against great odds - and have found the process made them happier and more hopeful.

Jamil's book Hope for Cynics: The Surprising Science of Human Goodness is out now.