Ask a dozen people to name a genius and the odds are that 'Einstein' will spring to their lips. Ask them the meaning of 'relativity' and few of them will be able to tell you what it is. The ABC of Relativity is Bertrand Russell's most brilliant work of scientific popularisation. With marvellous lucidity he steers the reader who has no knowledge of maths or physics through the subtleties of Einstein's thinking: in easy, assimilable steps, he explains the theories of special and general relativity and describes their practical application (amongst much else, discoveries about gravitation and the invention of the hydrogen bomb). The basic principles of relativity have not changed since Russell first publisehd his lucid guide for the general reader. This new edition takes account of the extension of our knowledge about the theory and its applications.