“Decca” Mitford lived a larger-than-life life: born into the British aristocracy—one of the famous (and sometimes infamous) Mitford sisters—she ran away to Spain during the Spanish Civil War with her cousin Esmond Romilly, Winston Churchill’s nephew, then came to America, became a tireless political activist and a member of the Communist Party, and embarked on a brilliant career as a memoirist and muckraking journalist (her funeral-industry exposÔe, The American Way of Death, became an instant classic). She was a celebrated wit, a charmer, and throughout her life a prolific and passionate writer of letters—now gathered here.