In 1954, Antonio Marussi started a series of symposia in Venice. The first three of these covered the entire theoretical definition of 3-D geodesy as delineated in discussions with renowned contemporary scientists, particularly Martin Hotine. After Marussi's death, the symposia were finally named the Hotine-Marussi Symposia and were continued in Italy. The Third Hotine-Marussi Symposium was held in L'Aquila from May 30 to June 3, 1994. It provided geodesists interested in theory and methodology with the opportunity to discuss their theoretical achievements, as well as new topics in the geodetic sciences. This book thus provides an updated overview of the main geodetic theories in various fields of application.