A tidal bore is a series of waves propagating upstream as the tidal flow turns to rising. It forms during spring tide conditions when the tidal range exceeds 4 to 6 m and the flood tide is confined to a narrow funnelled estuary. Its existence is based upon a fragile hydrodynamic balance between the tidal amplitude, the freshwater river flow conditions and the river channel bathymetry, and it is shown that this balance may be easily disturbed by changes in boundary conditions and freshwater inflow. This book demystifies the physics of a tidal bore and it thoroughly documents the tidal bores on our planet with reliable and accurate information. It aims to cultivate a passion for a beautiful, but fragile geophysical process, with in-depth updated content and by over 190 illustrations and photographs.