Atom-probe field ion microscopy is currently the only technique capable of imaging solid surfaces with atomic resolution, and at the same time of chemically analyzing surface atoms selected by the observer from the field ion image. Field ion microscopy has been successfully used to study most metals and many alloys, and recently good field ion images of some semiconductors and even ceramic materials such as high temperature superconductors have been obtained. Although other microscopies are capable of achieving the same resolution, there are some experiments unique to field ion...