War has been a fact of life for centuries. By lucidly revealing the common threads that connect the ancient confrontations between Athens and Sparta and between Rome and Carthage with the two calamitous World Wars of the twentieth century, renowned historian Donald Kagan reveals new and surprising insights into the nature of war and peace. Vivid, incisive, and accessible, Kagan's powerful narrative warns against complacency and urgently reminds us of the importance of preparedness in times of peace.