Summary form only given, as follows. In a very short time the scanning tunneling microscope (STM) has become an important surface analysis tool for real-space imaging of surface structure on an atomic scale. The visualization of atoms on a surface and even distinguishing one element from another can be performed routinely in many labs around the world. This technique has been extended to imaging organic adsorbates on conducting surfaces. The STM can resolve individual molecules and can even distinguish individual parts within complicated molecules. While the primary use of the STM has been as an imaging tool and sensitive topographical mapper, recently efforts have been made to use the STM as a manipulator of materials. Two applications are lithography and molecular manipulation including transformations on single molecules.