Zakaria admits that the title is a little misleading. He holds that America will remain the world's primary power for most of the forseeable future. This is particularly true in military terms. However, in relative terms, other powers will have more and more influence, especially at regional level. Thus, the "Post-American" world is not post-American, merely a world where "The rest", that is, other countries, increase their power and influence, thus diluting America's unchallenged role. So, the world will not be post-American in the sense America ceases to have an influence, it will be post-American in that it will no longer be America alone which decides the direction and character of the international system.
Zakaria then looks at the BRIC countries (Brazil, Russia, India, China), and notes how their dizzying rates of economic growth will eventually make the international economic system less Anglo-American in character as the century progresses. However, he argues that far from these cultures competing, there will be cross pollenation. This is particularly true of India, which has a rich tradition of absorbing new influences, and its background as a British colony means it is already well acquainted with how to cope in an Anglophone global economic system. His coverage of India and China's rise is very interesting. Zakaria argues that far from attempting to build an anti-Chinese balancing bloc amongst Asian allies like South Korea and Japan, America should extend the hand of friendship to China. This will draw China into a web of international law and trade, rather than isolate it and thus making it more bellicose.
One of the most interesting parts of the book is when Zakaria dismisses that Islamic extremism constitutes a serious rival to the West. This is a sharp departure from most American literature on radical Islam. He states that sluggish growth in Muslim countries, and frictions over women's roles in the economy place them at a disadvantage. Also, he believes that Al Qaeda is rapidly losing influence. At one point he mocks them as being little more than a video production company. Indeed, their war in Iraq was meant to unite all Muslims behind their anti-American message. Instead, all Al Qaeda in Iraq have done is kill other Muslims (Shia), and drive away Muslim support.
All in all, the book is light reading. It is an interesting view of how the 21st century may pan out, and anyone with an interest in international relations should consider reading it.