Publisher Summary This chapter provides an overview of visualization techniques in computational science. The kind of full color, 3-D, fully rendered, animated images that are produced from supercomputer numerical simulations of developing tornadic clouds represent the state of the art in visualization techniques. The chapter explains desktop visualization. The choice of the Macintosh emphasizes the importance of the user interface in providing a wide base of user access to methods of visual data analysis. The data from the simulations, or from experiments, or remote sensing devices, are complex enough or simply large enough; this is the reason why visualization techniques are useful in data analysis. The basic data-revealing step that is common to all visualization techniques is the mass of numbers transformed into a recognizable image or visual pattern. The chapter further explains standards for data formats.