Originally published in 1995, Monitoring Active Volcanoes is a comprehensive text which addresses the importance of volcano surveillance in the context of forecasting eruptive activity and mitigating its effects. The traditional core of seismic and ground deformation monitoring is discussed, along with more innovative techniques involving the recording of microgravity and micromagnetic variations, and the changing compositions of volcanic gases and liquids. The role of satellites is stressed, particularly with regard to the capabilities for measuring surface deformation, recognizing thermal anomalies and monitoring gas and ash plumes from space platforms. This book provides an invaluable insight into how and why volcanoes are monitored. It will be of interest to volcanologists, geophysicists and earth scientists.