For a century or more, nearly all technological advances have depended on our ability to produce and manipulate the vast variety of materials that nature has given us. Nowhere is that dependence more evident than in the field of electronics. From a smorgasbord of semiconductors, polymers, and metals, we've been able to create a dazzling array of circuitry that now underpins pretty much every aspect of modern life. So now imagine what we could do if we weren't limited to the materials found in nature. Researchers have long believed that it would someday be possible to produce artificial materials, or "metamaterials," and that they would bring about some stunning, otherworldly technologies-the sort that have figured in science fiction tales for years. These innovations include invisibility cloaks that could mask the presence of objects or their electromagnetic signatures, "unfeelability cloaks" that could mechanically mask the tactile feel of an object, superlenses that could resolve features too small to be seen with ordinary microscope lenses, and power absorbers that could capture essentially all of the sunlight hitting a solar cell.