Oops...Let me put that in the active voice: All economics students should read it.
As long as I am on the topic, let me also recommend William Zinsser's On Writing Well.
Random Observations for Students of Economics
I am the Robert M. Beren Professor of Economics at Harvard University, where I teach introductory economics (ec 10). I use this blog to keep in touch with my current and former students. Teachers and students at other schools, as well as others interested in economic issues, are welcome to use this resource.