The Guns of August is considered to be Barbara Tuchman's best book. It still stands up well, despite being more than fifty years old. In 1966, Barbara Tuchman consolidated several long essays that she published in magazines before she wrote the Guns of August, in her book "The Proud Tower: A Portrait of the World Before the War 1890-1914". This book looks at the politics of the United States and Great Britain, the Dreyfus affair in France, the culture of pre-war Germany and the various Socialist movements in Europe.
"A Distant Mirror: The Calamitous 14th Century" is also well received by historians. It deals with the Black Death, the Hundred Years War and the split in the Catholic church that saw the Avignon Papacy. She tells these stories through the life of Enguerrand de Coucy VII, a powerful French noble that was in the center of all this activity.