Thomas Piketty - Capital in the 21st Century Distributional effects of the current economic system have received growing interest as the distribution of income and wealth within the largest economies has grown steeper. It seems that this month, Capital in the 21st Century is on the bedside table of every economist I know, as Michael Lewis's book is on the table of every trader. And as with Flash Boys, everyone's has a problem or two with Piketty's theses, while the consensus is that it's an important book even after taking the flaws into account. Brad DeLong's "Finger exercises" provide a simple model to play with, and begins with a discussion of four different possible return rates (r) that might relate to the growth rate (g) in Piketty's models. He then