Peter Liddel offers a fresh approach to the old problem of the nature of individual liberty in ancient Athens. He draws extensively on oratorical and epigraphical evidence from the late fourth century BC to analyse the ways in which ideas about liberty were reconciled with ideas about obligation, and examines how this reconciliation was negotiated, performed, and presented in the Athenian law-courts, assembly, and through the inscriptional mode of publication. Using modern political theory as a springboard, Liddel argues that the ancient Athenians held liberty to consist of the substantial obligations (political, financial, and military) of citizenship.
Zeus knows I tried to muddle through this book, but I gave up after the third attempt. It seems to contain some interesting observations (that's why I tried to read it thrice) but I'm not sure how many, because it's so poorly written and terribly structured, that it's virtually unreadable.