Since the discovery of the hydrated electron in 1962, scientists have speculated over its vertical binding energy (VBE). In this book, the author describes the sophisticated experiments which finally made this quantity accessible and additionally revealed fascinating information about electrons bound at the liquid water surface. These results are crucial for understanding many electron transfer and attachment processes, ranging from radiation induced DNA damage to atmospheric chemistry. This book examines solvated electrons in liquid water and at liquid water interfaces, explaining their binding energies, lifetimes and the implications of these physical properties.