This book is devoted to the development of adequate spatial representations for robot motion planning. Drawing upon advanced heuristic techniques from AI and computational geometry, the authors introduce a general model for spatial representation of physical objects. This model is then applied to two key problems in intelligent robotics: collision detection and motion planning. In addition, the application to actual robot arms is kept always in mind, instead of dealing with simplified models. This monograph is built upon Angel del Pobil's PhD thesis which was selected as the winner of the 1992 Award of the Spanish Royal Academy of Doctors.