Your special report on the world economy boasts of a stunning sweep: the earliest year mentioned is 1700 while the latest is 2024 (“A Game of Catch-Up,” September 24, 2011). Congratulations! A visiting Martian would learn a good deal about economic development on earth from your pages. The emerging world is doing rather well. Although it may have to wait a bit longer than it wishes for its ultimate victory over the rich world, its course is straight. But the innocent visitor would be confused by one sentence in the concluding section: “If China can avoid a blow-up in the next decade, it is likely to become the world’s biggest economy.” A blow-up? There is not a word in the report about such a nasty event, though. “If Germany had managed to avoid a couple of blow-ups in the last century,” you could have helped a bit, “it could have become the world’s biggest economy by now.” Indeed, it is those unfortunate blow-ups that define much of economic development to date. Where would America be without the blow-ups that deterred Germany, for example? One way or another, your special report ends up by confusing the poor Martian. For the next report on the world economy, I would sincerely recommend a bit more information about the assorted blow-ups, of which there have been many in more than three centuries you cover so earnestly.