Thomas Piketty: A guide to economist's view of inequality gap
French economist Thomas Piketty is causing a stir with his new book about the gap between rich and poor.
In Capital in the Twenty-First Century, he says that while inequality reduced in the 20th Century, it is now rising - a situation Piketty thinks is hugely dangerous.
In this animated guide, Newsnight policy editor Chris Cook talks you through some of Piketty's data collection and analysis and his controversial policy suggestions.
Animation by Aslan Livingstone-Ra