This book intends to answer the following questions: What made it possible to create the Cavendish Laboratory in the 1870s? What was the Laboratory's principal role within Cambridge University and how did this role change over time? Who performed research at the Cavendish, when did they work there, and what topics did they investigate? In what ways and to what extent did the Laboratory's directors influence the work of Cavendish researchers? How did the Cavendish become the mecca of experimental physics during the first third of the twentieth century? In short, why was the Cavendish Laboratory so successful? In his search for the most plausible answers, the author makes clear that the history of Cavendish Laboratory is not only the story of a successful physics laboratory but also the story of great men.