Sir Edward Grey (1862-1933) was Britain's longest-serving Foreign Secretary, holding office from December 1905 to December 1916. Best known today for his observation on the eve of World War I, "The lamps are going out all over Europe; we won't see them lit again in our lifetime," Grey had worked tirelessly to keep the lamps on, while keeping Britain and the Empire secure. During his eventful and stressful years in office, and before and after, Grey corresponded extensively with Katharine Lyttelton (1860-1943), the wife of a high-ranking general who served as the first Chief of the General...