This chapter discusses the recent trends in Foreign Direct Investment (FDI) and a few theories explaining those trends. The main goals are to: Describe the importance of FDI in the world economy, and the changing geographic and sectoral patterns of FDI over time; explain the benefits and costs of FDI for host and home countries; present a number of different theories that attempt to explain the FDI rationale; outline the interlinkages between international trade and FDI.