But... liberty from what?

Almost every moralist in the history of mankind has praised liberty.

Like happiness and goodness, like nature and reality, the meaning of this term is so porous that there are few interpretations it seems able to resist.

What is liberty?

And what differences are there between the freedom advocated by liberal philosophers (negative liberty)
and the freedom defended by rational philosophers (positive liberty)?

What are the implications of defending negative liberty from the liberal arguments of Mill, Locke, and Constant?

What are the implications of defending positive liberty from the rational arguments of Kant, Rousseau, and Marx?

"Two Concepts of Liberty" explores the answer to these questions with great simplicity and reasonableness.