What is the smallest thing we can see? The fundamental limit on the size of an object that can be visualized with a light microscope is typically about half a micrometer. In this book of articles based on recent Evening Discourses at the Royal Institution, Akira Tonomura explains how electron waves can be harnessed to unveil the hitherto invisible microcosmos; Lewis Wolpert writes on the unnatural nature of Science; Harold Kroto retells the events leading to the discovery of buckminsterfullerene; and Tony Benn discusses science and political power. These and other essays are authoritative and accessible summaries of current thinking in many areas of science and technology.