This document summarizes preliminary findings from the OECD Human Capital Project. It presents background on measuring human capital as a determinant of economic growth and inequality. It describes the genesis and features of the OECD project, including participating countries and data sources. Preliminary results show levels and distribution of human capital by gender, education, and age. Volume changes in total and per capita human capital are also presented. Planned developments include improving estimates, constructing accumulation accounts, and analyzing how human capital measures can be used to improve economic analysis. Long-term challenges include incorporating quality measures and extending monetary measures to non-economic returns.