In 1939, seventeen-year-old Mary found herself in an extraordinary position at an extraordinary time: it was the outbreak of World War II and her father, Winston Churchill, had been appointed First Lord of the Admiralty; within months he would become prime minister. The young Mary Churchill was uniquely placed to observe this remarkable historical moment, and her diaries-most of which have never been published until now-provide an immediate view of the great events of the war, as well as exchanges and intimate moments with her father. But these diaries also capture what it was like to be a young woman during wartime. An impulsive and spirited writer, full of coming-of-age self-consciousness and joie de vivre, Mary's diaries are untrammeled by self-censorship or nostalgia. From aid raid sirens at ten Downing Street to seeing action with the women's branch of the British Army, from cocktail parties with presidents and royals to accompanying her father on key diplomatic trips, Mary's wartime diaries are full of color, rich in historical insight, and a charming and intimate portrait of life alongside Winston Churchill during a key moment of the twentieth century.