This paper provides a framework and estimates of Enrollment Rates per natural and combines them with previous Income and Child Mortality per natural estimates by Clemens and Pritchett (2008) to produce a Human Development Index Per Natural. The methodology is applied for 1990 and 2000 to provide estimates of growth rates of this measure over the period. The paper also develops and illustrates a framework for estimating an education place premium, and discusses how it is related to per natural measures. The peoples of the least developed countries stand to gain the most from international migration, but there are potentially significant gains to
migration between developing countries as well.