1997 saw the centenary of one of the most important moments in modern physics - the discovery of the electron. This volume maps the life and achievement of J.J.Thomson, with particular focus on his ideas and experiments leading to the landmark discovery. A foreword by J.J.Thomson's grandson, David Thomson, provides valuable insights into Thomson's personality, while the reproduction of original papers allows the reader to appreciate Thomson's own style and way of thinking. The book describes his early years and education, then taking us through his career at Cambridge, first as a Fellow of Trinity College, later as head of the Cavendish Laboratory and finally as Master of Trinity and national spokesperson for science. * An accessible historical survey of the discovery of the electron * Published to coincide with the centenary of the discovery in 1997 * A carefully researched account of J.J.Thomson's life and experiments leading to the discovery * Foreword by Thomson's grandson * Contains previously unpublished photographs from the Cavendish Science Museum, from David Thomson's personal collection, and facsimilie extracts from original science papers