 Howard McGary and Bill E. Lawson’s Between Slavery and Freedom: Philosophy and American Slavery (1992), is an indispensable source for philosophical analyses of these arguments, and the engagement of normative philosophy with historical and sociological theories of U.S. slavery, and Nicholas Buccola’s The Political Thought of Frederick Douglass: In Pursuit of American Liberty (2012), provides an excellent analysis of how Douglass’s critical examination of slavery fits into his liberalism and dominant conceptions of liberty of his time. An early, key contributor to the philosophical literature on Douglass, and to American philosophical literature on Douglass was Angela Davis, who of course is a key figure in the U.S. Civil Rights Movement and the emergence of both the black power movement and black feminism since the 1960s. Her groundbreaking essay on Douglass, “Unfinished Lecture on Liberation-II”, argued for an active rather than static conception of liberty, drew on and criticized Rousseau’s conception of slavery, and applied her analysis to the Civil Rights struggles she was involved in during the late 1960s and early 1970s ([1971]  1983).[7]