Having mentioned the principle of ‘comparative advantage’ recently, I’ve been looking for a good explanation of it on the web. It’s taken a little while, but this piece about David Ricardo’s theory seems to set it out relatively well.
What is missing is—as usual with explanations of this theory—any discussion of the costs of production and transport beyond the economic. For me, the failure to put economics in a social-environmental context is what lets down most such arguments.