A brief history of the observation of Piton de la Fournaise central area.- Geodynamic setting of La Réunion Island.- The construction of La Réunion Island.- Geology and morphostructure of Piton de la Fournaise.- Erosion and volcaniclastic sedimentation at Piton de La Fournaise: from source to deep marine environment.- Magma paths at Piton de la Fournaise volcano.- Pre-historic explosive activity at Piton de la Fournaise volcano.- Fifteen years of intense eruptive activity (1998-2013) at Piton de La Fournaise volcano (La Réunion): A review.- Petrological and experimental constraints.- A review of the recent geochemical evolution of Piton de la Fournaise volcano, Réunion Island (1927-2010).- Magma degassing at Piton de la Fournaise volcano.- Static and dynamic seismic imaging of Piton de la Fournaise.- Seismic monitoring at Piton de la Fournaise.- Ground deformation at Piton de la Fournaise (La Reunion Island), a review from 20 years of GNSS monitoring.- The March-April 2007 eruptions of Piton de la Fournaise as recorded by interferometric data.- Contribution of tiltmeters and extensometers to monitor Piton de la Fournaise activity.- A Geographical Information System for mapping eruption risk at Piton de la Fournaise, Reunion Island.- Perception of risk for volcanic hazard in Indian Ocean: La Réunion Island case study.- Groundwater resources: Conceptual models.- The volcanism of the Comores archipelago integrated at a regional scale.- Structure and history of Karthala.- Geochemical and Petrological aspects of Karthala.- Groundwater prospection in Grande Comore Island - Joint contribution of geophysical methods, hydrogeological times-series analysis and groundwater modelling.- Volcanic risk and crisis management on Grande Comore island.