What if every single time you bought a coffee from Starbucks, you felt an extreme amount of moral guilt? After all, 2 dollars donated to Oxfam can have a significant effect on real people that are really suffering in the world. This is a fascinating look at the personal stories and science behind and opinions about "do gooders." And we are not talking about merely nice people (sometimes they're not pleasant). These are moral saints, people who take morality to the extreme, who get rid of all their stuff and travel to a foreign country to save lives.
The book has a nice structure. A chapter about a do-gooder is followed by the history of what culture has thought about do-gooders in general - whether that be philosophy, religion, psychology, literature, or common sense. Throughout history, do-gooders have made is uncomfortable, and therefore we have been skeptical about them.
I think do-gooders come in two different flavors. First, there are people who have intense empathy. When they think about a person drowning, the feel as though their own child is literally drowning. These people can easily become moral saints. Second, there are people who take moral principles seriously. Utilitarian morality, for example, says that we should relieve the greatest amount of suffering for the greatest amount of people. If we took that seriously (as the philosopher Peter Singer has argued), we would instantly donate most of our income to Oxfam, leaving just enough money for us to subsist. That's a haunting thought for some people.
Conclusion: the writing style of this book is very run-on. It took me a lot of patience, but was worth it.