Never in human history was there such a chance for freedom of expression. If we have Internet access, any one of us can publish almost anything we like and potentially reach an audience of millions. Never was there a time when the evils of unlimited speech flowed so easily across frontiers: violent intimidation, gross violations of privacy, tidal waves of abuse. A pastor burns a Koran in Florida and UN officials die in Afghanistan.

Drawing on a lifetime of writing about dictatorships and dissidents, Timothy Garton Ash argues that in this connected world that he calls cosmopolis, the way to combine freedom and diversity is to have more but also better free speech. Across all cultural divides we must strive to agree on how we disagree. He draws on a thirteen-language global online project - freespeechdebate.com - conducted out of Oxford University and devoted to doing just that.

With vivid examples, from his personal experience of China's Orwellian...