Margaret MacMillan is Emeritus Professor of International History, University of Oxford and Professor of History, University of Toronto.

She is the author of Women and the Raj and the international bestsellers Nixon in China and Peacemakers, which won the 2002 Samuel Johnson Prize, and The War that Ended Peace, The Uses and Abuses of History and History's People, all published by Profile.

George Monbiot is an author, Guardian columnist and environmental campaigner. His best-selling books include Feral: Rewilding the Land, Sea and Human Life and Heat: How We Can Stop the Planet Burning; his latest is Out of the Wreckage: A New Politics for an Age of Crisis. George cowrote the concept album Breaking the Spell of Loneliness with musician Ewan McLennan, and has made a number of viral videos. One of them, adapted from his 2013 TED talk, How Wolves Change Rivers, has been viewed on YouTube over 40 million times. Another, on Natural Climate Solutions, which he co-presented with Greta Thunberg, has been watched over 60 million times.

Hannah Arendt was born in Hanover, Germany, in 1906, and received her doctorate in philosophy from the University of Heidelberg. In 1933, she was briefly imprisoned by the Gestapo, after which she fled Germany for Paris, where she worked on behalf of Jewish refugee children. In 1937, she was stripped of her German citizenship, and in 1941 she left France for the United States. Her many books include The Origins of Totalitarianism (1951), The Human Condition (1958) and Eichmann in Jerusalem (1963), in which she coined the famous phrase 'the banality of evil'. She died in 1975.

Tariq Ali has written more than two dozen books on world history and politics the most recent of which are The Obama Syndrome, The Extreme Centre and The Dilemmas of Lenin as well as the novels of his Islam Quintet and scripts for the stage and screen.

He is a longstanding member of the editorial committee of New Left Review and lives in London.

Noam Chomsky is Institute Professor in the Department of Linguistics and Philosophy at the Massachusetts Institute of Technology, Boston. A member of the American Academy of Science, he has published widely in both linguistics and current affairs.

His books include At War with Asia, Towards a New Cold War, Fateful Triangle: The U. S., Israel and the Palestinians, Necessary Illusions, Hegemony or Survival, Deterring Democracy, Failed States: The Abuse of Power and the Assault on Democracy and Manufacturing Consent: The Political Economy of the Mass Media.

Noam Chomsky was recently named the world's number-one public intellectual in a poll by Prospect magazine. He is the author of numerous bestselling political works, including Hegemony or Survival, Imperial Ambitions and Failed States, all of which are published by Hamish Hamilton and Penguin.

Noam Chomsky is a professor in the Department of Linguistics and Philosophy at MIT, and is widely credited with having revolutionized modern linguistics.