The essays in this volume assess the influence of intelligence on the Second World War and open up a number of other important areas for research. Studies of the growth of the imperial intelligence network cast new light on subjects ranging from Canadian surveillance of Vancouver Sikhs to signals intelligence in the Middle East. Studies of Japanese intelligence indicate the significance of Asian intelligence systems as a factor in modern international relations.A number of contributors emphasize the slowness with which governments and high commands learned to assess and use the intelligence they received.