Every step away from economic liberty takes us closer to authoritarian control over the whole of society. With central control comes corruption, servitude, and relative impoverishment. The difference between the Reds and Browns, Hayek argued, matters in theory but not in practice: both paths lead to serfdom. 

This argument shocked a generation of intellectuals who — very much like now — refuse to consider the integral relationship between liberty generally and freedom in the economic realm.

The timing of the book is significant. The world had been at war. Even countries with relatively free economies turned to economic planning and political centralization for the duration. Hayek regarded this path as deeply dangerous, one that threatened to convert free nations into the very thing they were supposedly fighting.

Popular wisdom regards this book as a warning against socialism, which is true enough, but a closer look reveals something striking: its primary warning concerns not Soviet-style socialism but rather the fascist form that was then sweeping Europe.