In a very negative review of Žižek's book "Less than Nothing", the British political philosopher John Gray attacked Žižek for his celebrations of violence, his failure to ground his theories in historical facts, and his ‘formless radicalism’ which, according to Gray, professes to be communist yet lacks the conviction that communism could ever be successfully realized. Gray concluded that Žižek's work, though entertaining, is intellectually worthless: "Achieving a deceptive substance by endlessly reiterating an essentially empty vision, Žižek's work amounts in the end to less than nothing."