The first edition of this popular book on particle physics received universal acclaim for its clear and readable style. In this second edition the authors have brought the subject right up to date, including the discovery of the 'top quark' and the search for the Higgs particle. The book is the result of a collaboration between a world-famous elementary particle physicist and a physicist specialising in popular science writing. Together they have produced a fascinating account of the search for the fundamental building blocks of matter. This lucid and entertaining accountwill fascinate anyone wishing to keep pace with this part of the progress of human knowledge, from scientifically educated general readers through to professional physicists.