John Rawls, author of A Theory of Justice, was perhaps the greatest philosopher of the 20th century.  As an undergraduate at Princeton in 1942, he submitted A Brief Inquiry into the Meaning of Sin and Faith: An Interpretation Based on the Concept of Community as his senior thesis. Decades later, Professor Eric Gregory of the Princeton religion department found this thesis in the Princeton Library, and now New York University Law professor Thomas Nagel has edited it into a book.