Our definition of a breakthrough is simple: an advance that gives people powerful new ways to use technology. It could be an intuitive design that provides a useful interface (see “Smart Watches”) or experimental devices that could allow people who have suffered brain damage to once again form memories (“Memory Implants”). Some could be key to sustainable economic growth (“Additive Manufacturing” and “Supergrids”), while others could change how we communicate (“Temporary Social Media”) or think about the unborn (“Prenatal DNA Sequencing”). Some are brilliant feats of engineering (“Baxter”). Others stem from attempts to rethink longstanding problems in their fields (“Deep Learning” and “Ultra-Efficient Solar Power”). As a whole, we intend this annual list not only to tell you which technologies you need to know about, but also to celebrate the creativity that produced them.

 —The Editors