“War! What is it good for?” Motown singer Edwin Starr asked in his 1969 hit record. The musical answer: “Absolutely nothing.” But in a discussion of his erudite new history of war, Stanford University’s Ian Morris takes the provocative position that, despite its horrors, armed conflict has made humanity both safer and richer. From the aggressive instincts of chimpanzees and early “protohumans” to ancient civilizations and the “American Empire,” he looks at war and notes that in terms of lives lost (as a percentage of national population), its impact has lessened while the long-term effects have been “productive.” Morris is the Willard Professor of Classics at Stanford.