Where once economies were built on industry and conquest, we are now part of a global information economy. The fourth edition of this classic study brings it up to date with new research and with social and technological changes - from the 'Twitter Revolutions' of North Africa, to financial crises that introduced the worst recession in a lifetime, to the emergence of social media and blogging - and reassesses the work of key theorists in light of these changes. More outspoken than previous editions, this interdisciplinary book is essential reading for those trying to make sense of social and technological change in the post-war era.