The stories and the thinking behind a range of world-changing inventions, from the wheel to the smartphone, are condensed into entries that can be read in half a minute in this addition to the "30-Second" series.

David Boyle is the author of several books about history, the history of ideas and the future. His Authenticity: Brands, Fakes, Spin and the Lust for Real Life helped put the search for authenticity on the agenda as a social phenomenon, while Funny Money: In Search of Alternative Cash launched the ‘time banks movement’ in the UK. His work on the history and future of money has also been published in many books and pamphlets. He has stood for Parliament and undertaken an independent review for the UK Treasury and Cabinet Office.