Are you referring to Economics in One Lesson? It looks like that's Henry Hazlitt, not Sowell. (Am I missing something?) It looks like DeLong has some criticism of that.

https://en.wikipedia.org/wiki/Economics_in_One_Lesson#Critic...

Just to be clear, I'm not an expert on any of this. I just popped in to provide a pointer I've found useful in learning about a topic when I'm not sure where to start. Similarly here, I just applied a bit of search-fu.