Originally published in 1942, this book provides a well-researched biography of the British physicist Sir Joseph John Thomson. Thomson's revolutionary discoveries relating to atomic structure are covered in detail, together with the scientific climate of the time and other non-scientific aspects of his life. The text contains numerous excerpts from Thomson's writings, including his letters, together with a variety of photographic figures. Produced shortly after his death in 1940 and written on the advice of his family, this book will be of value to anyone with an interest in Thomson's life and achievements.