Duncan Watts is a principal research scientist at Yahoo! Research, and a former professor of sociology at Columbia University. His research on social networks and collective dynamics has appeared in a wide range of academic journals, including Nature, Science, and the American Journal of Sociology. He is also the author of two previous books, Six Degrees: The Science of a Connected Age; and Small Worlds: The Dynamics of Networks between Order and Randomness. Duncan's latest book is Everything is Obvious* *Once you Know The Answer: How Common Sense Fails.

First broadcast on 29th July 2011.