As the use of geographical information systems develops apace, a significant strand of research activity is being directed to the fundamental nature of geographic information. This volume contains a collection of essays and discussions on this theme. What is geographic information? What fundamental principles are associated with it? How can it be represented? How does it represent the world? How can geographic information be quantified? How can it be communicated and related to the other information sciences? How does HCI tie in with it? A number of other more specific but relevant issues are considered, such as Spatio-temporal relationships, boundaries, granularity and taxonomy. This book is a revised and updated version of a collection of presentations given by a group of distinguished researchers in the field of Geographic Information Science who gathered in Manchester in July 2001. It should be useful for graduate students as well as researchers and high-level professionals.