Why is the Victoria Line so hot? What is an Electrical Multiple Unit? Is it really possible to ride from King's Cross to King's Cross on the Circle line?The London Underground is the oldest, most sprawling and illogical metropolitan transport system in the world, the result of a series of botch-jobs and improvisations.Yet it transports over one billion passengers every year - and this figure is rising.It is iconic, recognised the world over, and loved and despised by Londoners in equal measure.Blending reportage, humour and personal encounters, Andrew Martin embarks on a wonderfully engaging social history of London's underground railway system (which despite its name, is in fact fifty-five per cent overground).Underground, Overground is a highly enjoyable, witty and informative history of everything you need to know about the Tube.