During the past decade, foreign participation in U.S. research and development - through acquisition of R&D-intensive businesses, links with universities, and other arrangements - has expanded rapidly. This emergence of foreign influence has drawn a mixed response - some regard the trend as a positive corollary to the expanding involvement of U.S.-owned companies in national markets abroad. Others consider it a net liability for Americans that often benefits foreign companies and their home economies at U.S. expense. There exists a large gap in expert and public understanding of the drivers, nature, and consequences of foreign participation in the nation’s technology enterprise. This volume seeks to close this gap and reviews: the nature of R&D activities and how they contribute to economic development; the causes, scope, and nature of foreign involvement in U.S.-based R&D activity and the associated costs, risks, benefits, and opportunities of this trend; and the merits and liabilities of policies to regulate foreign R&D participation.