Wikipedia has been hailed as the most revolutionary aid to the spread of human knowledge since Gutenberg's printing press. In less than a decade it has single-handedly invigorated and torn up the very idea of an 'encyclopedia'. Today Wikipedia is firmly entrenched in the world's top 10 web sites. It has become so popular we casually stumble across its content every day. Type any word into any search engine and more than likely a Wikipedia page will be the first result. It is increasingly cited in the press, books, legal affairs and politics. But whereas the only web brands that consistently rank above it - Google, Yahoo and Microsoft - are multi-billion dollar enterprises, each with tens of thousands of employees, Wikipedia has a paid staff of just 10, with an operating budget of little more than $3 million. Instead it depends entirely on a legion of unpaid, often anonymous, volunteers. And, since January 2001, these 'Wikipedians' have created more than 10 million articles, in over 250 lanuguages, adding and updating at 'the speed of news' to create nothing less than a 'continuous working draft of history'.But success hasn't come without controversy and whilst many regard it as a great liberator, others - from universities to the People's Republic of China - see only anarchy and chaos. So now, for the first time, Andrew Lih tells the Wikipedia story. A story which challenges some of our most cherished notions - from neutrality, authority and ownership to civil liberties and the profit motive - and explains how a bunch of geeks built the world's greatest encylopedia. Andrew Lih is an academic who writes and commentates on new media, journalism and technology. He has taught at Columbia University and the University of Hong Kong.