Room 40: British Naval Intelligence 1914-18 (1982) By Patrick Beesly
 
This book is the enthralling story of the extraordinary band of amateurs in Room 40 - university professors, clergymen, naval schoolmasters, stockbrokers, and bankers - who captured all the German naval codes before the end of 1914 and of how they read them and their replacements over the next four years.
 
Hard Cover with Dust Jacket
338 pages
Good condition