The Mirrlees Review represents the culmination of four years of effort by a large team of tax experts drawn from around the world. These tax experts began by examining in detail a broad range of issues dealing with the existing tax structure in the United Kingdom, generating a huge tome of studies and commentary: Dimensions of Tax Design. Based on these studies, a smaller group of distinguished economists compiled a comprehensive set of proposed reforms to the UK tax structure, as described in their volume, Tax by Design: The Mirrlees Review. Such a comprehensive study is a worthy successor to the Meade Committee Report (Meade 1978), a report also issued by the Institute for Fiscal Studies that has provided the backbone for all discussions since that time of broad-based income taxes. Tax by Design: The Mirrlees Review also should form the underpinning for tax-reform discussion for many years, and not only in the United Kingdom.

Whereas from a political perspective, the reforms proposed in the Review may seem dramatic, even radical, they all will receive strong support from most tax economists and are well supported by the existing academic research. Past research, however, by intent does not speak with one voice. In my role as a commentator, I focus on the remaining debate in the academic literature. Given how extensive the proposed reforms are, I divide my comments into two parts, with this part focusing on the proposed reforms to the taxation of labor income and transfers linked to labor income. In the other part, Gordon 2011 discusses the remaining proposed reforms, largely those dealing with the taxation of income from savings and investment.