In the "book description" the writer (who is, most likely, not the author of the book) claims that modern writers "struggle" to defend the free market in the face of the current economic crises - as the present economic system is NOT a free market (it is government dominated mess) this claim is absurd.
Also the writer of the "book description" claims that the leading free market writers of the 1930s (Ludwig Von Mises, Hayek and so on) were alert to the "problems of capitalism" (implying that "capitalism" was responsible for the Great Depression - whereas it was actually the case of these writers that government interventionism, specifically the expansion of the money supply in the late 192s and the radically statist response to the bust of 1929, was responsible for the Great Depression).
Then the writer of the "book description" claims that Milton Friedman and others developed a "more strident" defence of the free market than had the Austrian School. This is the exact opposite of the truth - as Milton Friedman actually accepted the state interventions (specifically the Irving Fisher backed government increase of the money supply to keep the "price level" stable).
In short - the "book description" is nonsense from start-to-finish. If the book is anything like the "book description" it is worthless.