Latvian born, English educated, and a cosmopolitan in the world of ideas, Isaiah Berlin was both a prolific public intellectual and a distinguished academic, concluding his career as Oxford University's Chichele Professor of Social and Political Theory. After publishing some early essays in analytical philosophy, Berlin soon turned to more historical studies. While favoring the essay form, he published an important book-length study of Marx (1939) that was critical of Marx's historical determinism in ways that anticipated his later critiques of theories of historical inevitability. During the Second World War, Berlin worked for the British government in the United States, after which he returned to teaching at Oxford University, with occasional sojourns in London and the United States. His practical political involvements lent a spirit of engagement to his writings, whatever the subject.

Berlin championed political theory at a time when it was distinctly unfashionable...