Although Sowell writes very convincingly and brings logical arguments at first sight, most of his statements on the free market are based on intuition rather than data. He consistently uses a handful of examples (minimum wage, housing market) and extrapolates those to other areas in the economy without substantiation. Always assuming a fully efficient market (which it is not, see different bubbles in past few decades), rational actors (i.e. ignoring human emotion and/or marketing effects that effect consumer spending) and full price elasticity of all goods/services/labor.
It's an interesting read, but be (very) skeptical. The world and economics is a bit more complex than the picture he portrays.
> assuming a fully efficient market (which it is not, see different bubbles in past few decades)
Well, I think it's part of the book to speak in favor of free markets as opposed to centrally planned "markets" (such as prices for money, e.g., interest rate).
If you're criticizing an underlying assumption, then of course I can also go ahead and criticize parts of mathematics for some of their axioms. Yet, that doesn't make mathematics wrong, only more limited in scope.
It's an interesting read, but be (very) skeptical. The world and economics is a bit more complex than the picture he portrays.