An Englishwoman of no particular fame living in World War I Brussels started a secret diary in September 1916. Aware that her thoughts could put her in danger with German authorities, she never wrote her name on the diary and ran to hide it every time the "Boches" came to inspect the house. The diary survived the war and ended up in a Belgian archive, forgotten for nearly a century until historians Sophie De Schaepdrijver and Tammy M. Proctor discovered it and the remarkable woman who wrote it: Mary Thorp, a middle-aged English governess working for a wealthy Belgian-Russian family in...