Single molecules of DNA can be visualized in solution by epifluorescence microscopy and manipulated by a variety of mechanical, electrical and chemical means. Experiments are described in which DNA molecules are moved and extended in electrical fields, guided by grooves on a glass surface, digested by nucleases, and picked up, translated and released by scanning tunneling microscope (STM) tips. The results presented represent a first step in the development of molecular scale surgery on cells and organelles and the use of polymers to fabricate molecular scale structures and devices.