About a month ago I watched a documentary entitled Capital in the 21st Century. It was pretty riveting, describing much of what, and how, I've been thinking  over the past few years about the American take-over of Canada, and the belief that the country "developed" largely because the very rich were too lazy, risk-averse and unpatriotic to invest in their own country, preferring instead to let the more adventurous Americans do the heavy lifting in exchange for a commission - collected by bankers, accountants and lawyers - which was then sent offshore, where returns were better, and taxes lower or non-existent.    The documentary, based on French economist Thomas Piketty's best-selling book of the same name (Harvard University Press, 2014) - a copy of which I've just bought for the second time - tells the story of how fights over capital resulted in two world wars, followed by a mid-century golden period during which the wild beast was tamed and the promise of a merit-based economic system, among other things, was briefly realized, until the animal was unleashed again thanks to Ronald Reagan and Margaret Thatcher. Today inequality is at the same frightful extremes experienced prior to the world wars. Will we repeat the same devastating mistakes, knowing what we now know?    The film is a warning; and director Justin Pemberton delivers it with all the power of his medium. I talk with the New Zealander (!) about how he went about converting Piketty's startling 800-page narrative of capitalism's past, present and future, into a fast-paced, thrilling, persuasive, on-screen polemic.