As millions of Americans prepare to file their income taxes ahead of Monday’s deadline, we look at how corporations and the wealthy use offshore banks and tax havens to avoid paying taxes and other governmental regulations. "Tax havens have grown so fast in the era of globalization, since the 1970s, that they are now right at the heart of the global economy and are absolutely huge," says our guest, British journalist Nicholas Shaxson. "There are anywhere between $10 and $20 trillion sitting offshore at the moment. Half of world trade is processed in one way or another through tax havens." Shaxson is the author of the new book, Treasure Islands: Uncovering the Damage of Offshore Banking and Tax Havens.