He strides the world in seven-league boots, armed with a powerful thesis: in the postcolonial, post-cold-war era, three superpowers have emerged with a ravenous appetite for energy and natural resources….The Second World is rewarding simply as a primer on contemporary geopolitics. Anyone curious about the lay of the land in Algeria or Tajikistan can get answers, and a dash of local color, in Mr. Khanna’s succinct chapters, which envelop the reader in a whirlwind of facts and figures….