It is unexpected in any era to find a woman writing a book on the art of warfare, but in the fifteenth century it was unbelievable. Not surprisingly, therefore, Christine de Pizan's The Book of Deeds of Arms and of Chivalry, written around 1410, has often been regarded with disdain. Many have assumed that Christine was simply copying or pilfering earlier military manuals. But, as Sumner Willard and Charity Cannon Willard show in this faithful English translation, The Book of Deeds of Arms and of Chivalry contains much that is original to Christine. As a military manual it tells us a great deal about the strategy, tactics, and technology of medieval warfare and is one of our most important sources for early gunpowder weapon technology. It also includes a fascinating discussion of Just War.