On Tuesday, Apple CEO Tim Cook testified in front of the Congressional Permanent Subcommittee on Investigations as a part of their look into the company’s corporate tax practices — according to Sen. Carl Levin, the chairman of the committee, “Apple successfully sought the holy grail of tax avoidance. It has created offshore entities holding tens of billions of dollars while claiming to be tax resident nowhere.” I asked Mihir A. Desai, a professor and dean at Harvard Business School, a professor at Harvard Law School, and the author of a 2012 HBR article on taxing businesses, a few questions about how this investigation fits into a larger debate about the corporate tax code. Our edited conversation is below.