Economics has been one field that I've long thought should be a required course in high school. Mostly because elections seem to hinge on how the economy is performing but most people are completely clueless about even the basics of the ideas being talked about in government to actually effect the economy at large. While a basic economics eduation wouldn't be a miracle cure, I do believe it would at least give people some very fundamental tools to follow the discussion.
This little book sounds like not a bad way to start. I don't have any real knowledge about what actually works for teaching economics but it certainly is an area that will require creative thinking to address, which this is an example of. The big barrier (aside from the basically impossible political ones of fundamentally changing curriculum, especially since you'd have the Austrians claiming that the macroeconomics being taught by any mainstream text is worse than nothign) is that people who haven't been introduced to economics relatively early tend to struggle a great deal with it, which is a category that would like include much of the teaching profession. One way around this is to have the 10th graders develop the text themselves. Of course, this may not be the best way, I have no idea what is, but breaking a new curriculum area into traditional education will definitely require a creative approach.
[Edit: The following has been incorporated into a separate post. Of course, in addition to economics there are plenty of other areas I'd like to see reformed in education. History being a big one of these. I'm constantly annoyed by the impression I get that people in most fields seem to think that aside from the Greeks, nothing worth knowing about happened before the 18th and 19th centuries. The world looks very different if you don't assume the 19th century was a good model for modern times, I'm going off on a tangent here so I'll leave it at that.]