Bernard Merkel 
Concept of Freedom and the Development of Sartre’s Early Political Thought [PDF ebook] 

This book, first published in 1987, is a study of the development of Sartre’s political thought from the late 1920s to the liberation of France in 1944, concentrating particularly upon his concept of freedom. It is argued that the evolution of Sartre’s thinking can be regarded as constituting a series of problematics each of which has a corresponding notion of freedom, and these problematics are elucidated in turn.