In "inventing" modern motion pictures, Thomas Alva Edison and William Kennedy Laurie Dickson developed a complex communications system-not a single invention but a whole group of inventions. While this achievement occurred within the framework of multifaceted influences-the work of Muybridge, Etienne-Jules Marey, and others; Edison's own prior accomplishments also shaped their thinking, the process of invention, and the way the developing motion-picture system was initially employed. In the 1870s Thomas Edison had established himself as the businessman's inventor. He was hired to make various improvements on the telegraph for Western Union, Jay Gould, and other financial powers then striving for dominance in the fields of communication and transportation. One of Edison's inventions, the quadruplex, could send four messages over one wire at the same time (two in each direction), an innovation that saved companies millions of dollars. He...