Electromagnetic distance measurement, by using light and microwaves for direct linear measurements and thus circumventing the need for traditional methods of triangulation, may well introduce a new era in surveying. This book brings together the work of forty-eight geodesists from twenty-five countries. They discuss various new EDM instruments-among them the Tellurometer, Geodimeter, and air- and satellite-borne systems-and investigate the complex sources of error. The book is therefore a unique and comprehensive source on the subject. UNESCO and R.I.C.S. have assisted financially in its production.