This document provides an overview of the MacArthur Foundation's Initiative on Global Migration and Human Mobility. It discusses the Foundation's goals of improving governance of international migration and understanding the relationship between migration and economic development. It summarizes the key topics discussed at the inaugural Global Forum on Migration and Development in Brussels in 2007, including how migration impacts countries of origin and destination. It also outlines some of MacArthur's grants focused on migration, such as supporting the second Global Forum in Manila and improving migration data collection.