Since their introduction in 1999, the "Electrostar" family of Electric Multiple Units replaced a large number of aging British Rail-designed stock dating back to the 1950s. Over the next two decades more than 600 Electrostars have been built. Today they can be found on many services in and around London and on routes radiating from the capital city. This book takes a look at the many different designs in this large family, and the many routes they can be found on.