Mr. Diamond’s book would have benefited from a breakdown of leadership into various traits—humility, arrogance, decisiveness—and a discussion of their bearing on success or failure. The author looks at such characteristics in his individual profiles, but he doesn’t report any studies that examine them across many cases, possibly because they don’t lend themselves to social-scientific measurement ... Mr. Diamond’s emphasis on common benchmarks for success—a country’s economic growth, a corporation’s profits—leaves unexplored the possibility that each unique leader might harbor his or her own criterion of achievement.