The advent of highly precise space-based geodetic techniques has led to the application of these techniques to the solution of global earth and ocean problems. Now under consideration is a worldwide network of interconnected fiducial stations where geodetic as well as other scientific measurements can be made. This book discusses the science rationale behind the concept of an extensive global network of fiducial sites. It identifies geophysical problems that cannot be solved without a global approach and cites geodetic objectives that call for a global deployment of fiducial sites. It concludes with operations considerations and proposes a plan for development of the global network.