According to the political theorist Alan Johnson there has been a revival of serious interest in communism in the 21st century led by Slavoj Žižek and Alain Badiou. Other leading theorists are Michael Hardt, Antonio Negri, Gianni Vattimo, Alessandro Russo, Jodi Dean and Judith Balso. Also Alberto Toscano, translator of Alain Badiou, Terry Eagleton, Bruno Bosteels and Peter Hallward. Many of these advocates contributed to the three-day conference, "The Idea of Communism," in London in 2009 that drew a substantial paying audience. Theoretical publications, some published by Verso Books, include The Idea of Communism, edited by Costas Douzinas and Zizek, Badiou's The Communist Hypothesis, and Bosteels's The Actuality of Communism. The defining common ground is the contention that 'the crises