Book excerpt: This book is a must for the marine community - including oceanographers, resource managers, geographers, nautical archaeologists, climate change specialists, and other students of the deep - coming at a time when the health of our oceans is seen as crucial to our very existence. As a teaching tool, Arc Marine: GIS for a Blue Planet serves as a perfect starting point for the intermediate student or as a resource for the expert in marine GIS. Marine researchers have developed a data model that supports seafloor mapping, fisheries management, marine mammal tracking, monitoring of shoreline change, and water temperature analysis. The ability to measure change in oceans and along coasts has increased as marine GIS has grown more complex. Arc Marine: GIS for a Blue Planet presents the initial results of a successful effort to create and define a data model for the marine community - that group of academic, government, military, and private oceanographers, resource managers, conservationists, geographers, nautical archaeologists, and others who support better management of complex spatial analysis in marine applications. The data model not only provides structure to storing and analyzing marine data but helps users create maps and three-dimensional scenes of the marine environment in ways invaluable to decision making as the marine community strives to understand, illuminate, chart, and explore the unknown depths.