Visualization is the process by which one is able to create and sustain mental images for observation, analysis, and experimentation. This study consists of a compilation of evidence from historical examples that were collected in order to document the importance and the uses of visualization within the realm of scientific investigation. Descriptions of Archimedes, Edison, Newton, Tesla, Kekule, Einstein, Faraday, Hawking, and Galileo's use of visualization are described. (Contains 41 references.) (PR)