The recurring theme of Lilla's writings is the contested heritage of the modern Enlightenment. His first book, "G. B. Vico: The Making of an Anti-Modern" examines an early figure in the European Counter-Enlightenment, and has an affinity with the works of Isaiah Berlin (with Ronald Dworkin and Robert B. Silvers, he edited the memorial volume, "The Legacy of Isaiah Berlin" in 2001.) In the 1990s he wrote widely on twentieth-century European philosophy, editing with Thomas Pavel the New French Thought series at Princeton University Press, and writing "The Reckless Mind", a meditation on the "philotyrannical" bent of twentieth-century continental philosophy. His wide-ranging study of modern political theology, "The Stillborn God", based on the Carlyle Lectures delivered at Oxford University in 2003, was named one of the "100 best books of the year" by "The New York Times Book Review" and one of the 150 best books of the year by "Publisher's Weekly." In 2015 he received the Overseas Press Club of America's award for Best Commentary on International News for a series of articles in "The New York Review of Books" on the French response to the terrorist attacks of that year. Those articles became part of "The Shipwrecked Mind: On Political Reaction", a study of how nostalgia has shaped modern politics, from Middle America to the Middle East. In recent years he has also been involved in public debates over the future of American liberalism and the Democratic Party, which is the focus of "The Once and Future Liberal".