University of Pennsylvania Professor Nader Engheta gives a brief introduction to the field of metamaterials: composite materials that are engineered to have electromagnetic properties that aren't found in nature. For example, metamaterials can be designed to "cloak" objects, bending light or other waves around them, rendering them invisible. In their latest study, Engheta and colleagues have laid out a theory for metamaterials that can do mathematical operations on the profiles of light waves. For one such material, the profile of an incoming light wave would be bent and manipulated such that the profile's derivative would come out the other side of the material. This video is also available on YouTube at http://www.youtube.com/watch?v=lK4RQr7RICY. This video relates to a paper that appeared in the 10 Jan., 2014, issue of Science, published by AAAS. The paper, by Alexandre Silva at University of Pennsylvania in Philadelphia, PA, and colleagues was titled, "Performing Mathematical Operations with Metamaterials."