This article presents results of innovative surveys that tracked academic high achievers from five countries to wherever they moved in the world to directly measure at the micro level the channels through which high-skilled emigration affects sending countries. There are high levels of emigration and of return and the income gains to the best and brightest from migrating are an order of magnitude greater than any other effect. Most high-skilled migrants from poorer countries remit but involvement in trade and foreign direct investment is rare. Fiscal costs vary widely but are much less than the benefits to the migrants themselves.