Understanding Digital Earth.- Part I Digital Earth Technologies.- Digital Earth Platforms.- Remote Sensing.- Satellites for Digital Earth.- Satellite Navigation for Digital Earth.- Geospatial Information Infrastructures.- Geospatial Information Processing Technologies.- Geospatial Information Visualization and Extended Reality Displays.- Transformation in Scale for Continuous Zooming.- Big Data and Cloud Computing.- Artificial Intelligence.- Internet of Things.- Social Media and Social Awareness.- Part II Digital Earth for Multi-domain Applications.- Digital Earth for Sustainable Development Goals.- Digital Earth for Climate Change Research.- Digital Earth for Disaster Mitigation Research.- Digital City: An Urban Perspective on Digital Earth.- Digital Heritage.- Citizen Science in Support of Digital Earth.- The Economic Value of Digital Earth.- Part III Digital Earth Regional & National Development.- Digital Earth in Europe.- Digital Earth in Australia.- Digital Earth in China.- Digital Earth in Russia.- Part IV Digital Earth Education and Ethics.- Digital Earth Education.- Digital Earth Ethics