Voices of conscience: why do some people take moral stands?

Why do people stand up for their principles, even when the results could lose them their jobs, or even their lives?

That's the question author Eyal Press asks in Beautiful Souls: Saying No, Breaking Ranks, and Heeding the Voice of Conscience in Dark Times.

A Swiss Police Commander disobeys orders and helps hundreds of Jewish refugees escape from Austria to Switzerland in 1938. A Serbian man saves his Croatian neighbours from abuse in a Serbian detention camp in the early 1990s. And a financial broker turns whistleblower after being fired for trying to prevent fraud.

There are many examples of evil lurking in conformity, when regular citizens stand by while others are in jeopardy. The characters in this book defy those stereotypes and stand against authority and apathy.

The book explores the psychology and science behind these ethical decisions - and Mr Press explains to the BBC why when the going gets tough, the tough stand their ground.