The book has been prepared following a workshop organized by ALERT Geomaterials on the topic of geological storage of carbon dioxide. It contains full size chapters dedicated to geosciences issues, physics of fluid issues and geomechanics issues pertaining to the development of CO2 storage facilities on shore and off shore. It presents an overview of multiphysics processes occurring in storage facilities. It deals with geophysical, geological and geomechanical issues related to CO2 storage in geological formations. The book is divided into three parts. The first one is dedicated to transport processes and focuses on the efficiency of the storage complex and on evaluation of possible leakage paths. The second part deals with issues related to reservoir injectivity and to the presence of fractures and occurrence of damage. The topic of the last part concerns serviceability and ageing of the geomaterials whose poromechanical properties may be altered by the contact with the injected reactive fluid.