Scientists are always pushing to new frontiers, which often involve questions about phenomena that occur on very large or very small scales. Astronomers search for new stars millions of light‐years away in a quest to learn how these stars and the universe were born, and particle physicists look at elementary particles of size less than10−17 cmin an effort to understand fundamental interactions. Meanwhile, however, many biologists, chemists and condensed matter physicists are trying to understand natural phenomena that we encounter every day and that occur on some intermediate scale. Questions at this scale are posed in terms of interactions between electrons or atoms and chemical bonds or in terms of atomic theories. The motivation is not only scientific curiosity but also a desire to discover new effects, create new molecules and materials, and develop new technologies that may benefit society. Although a single interaction, electromagnetism, determines the chemical and physical properties of molecules and materials, nature manifests electromagnetic forces in so many forms and in so many phenomena that many of them are by no means understood. One of the powerful tools at our disposal for studies on the microscopic scale or atomic scale is the atomic‐resolution microscope.