Are we prepared for a world where people print guns? We better be; Advances in 3D printing have led to difficult issues for law and government. In this episode we talk with Jonathan Zittrain, a law and computer science professor at Harvard and co-founder of the Berkman Center for Internet. He explains how 3D-printing technology is being used to make guns and gun parts, and explores how the do-it-yourself gun industry might be regulated in the future.