This book belongs with Hayek's "The Road to Serfdom" in its timelessness. Sowell put together another masterpiece of incredible scholarship. Behind the title of the book is its premise that failed liberal policy is a result from a fallacious implicit worldview that the left wing holds, namely, that They are the Annointed, send from God to save us all.
He presents this premise by showing self-congratulation at the end of numerous failed social policies (this book reads not only as good nonfiction but as an excellent source of statistical information!). Sowell uses quotes from before and after each liberal fiasco, and finishes his analysis by presenting an alternate Vision, the "tragic vision."
As much as I like Sowell, his tragic vision (based on a very dim view of human nature) conceeds the moral, idealistic argument to the left, as every conservative has done for decades. Still, his biting criticism of the left is necessary reading for any freedom advocate. Buy it now.