[jswinghammer]

I'm going to go out on a limb here and say he probably knows what to recommend because he spends time reading. When you read something it's good to read up on the beliefs of the author on a variety of topics and get a sense of where their biases might trend. Normally this isn't very hard once you know what to look for.

The key is usually to identify the larger debate going on and make sure you know the different sides. For instance if you're going to read a book by Milton Friedman it's helpful to read up on the various schools of economics to see where he fits into that debate. I believe the term that applies here is erudition. You want that.