Economist Dani Rodrik has a great essay up on his website on what's good and bad about economics. Here's a bit on the relationship between trade policy and growth:
I remember well the reception I got when I presented my paper (with Francisco Rodriguez) on the empirics of trade policy and growth. The literature had filled up with extravagant claims about the effect of trade liberalization on economic growth. What we showed in our paper is that the research to date could not support those claims. Neither the theoretical nor empirical literature indicated there is a robust, predictable, and quantitatively large effect of trade liberalization on growth. We were simply stating what any well-trained economist should have known. Nevertheless, the paper was highly controversial. One of my Harvard colleagues asked me in the Q&A session: “why are you doing this?” It was a stunning question. It was as if knowledge of a certain kind was dangerous.
There's a lot of good material in there about what economics is and isn't, and how to do it better. I had forgotten that Rodrik studied at Princeton, so was pleasantly surprised by this:
However, contemporary economics in North America has one great weakness, and that is the excessive focus on methods at the expense of breadth in terms of social and historical perspective. PhD programs now train applied mathematicians and statisticians rather than real economists. To become a true economist, you need to do all sorts of reading – from history, sociology, and political science among other disciplines – that you are never required to do as a graduate student. The best economists today find a way of filling this gap in their education. I consider myself very lucky that I was a political science major and did a master’s in public affairs (as it is called at Princeton) before I turned to economics. I say lucky, because some of my best work – by my judgement, at least – was stimulated by questions or arguments I encountered outside of neoclassical economics.