In response to Osprey, whose post on her first computer was very different from my first experiences, I want to share my early typesetting days. Above you see an IBM Selectric. In 1980, when I was hired by a New York City department store to do paste-up and typesetting in their art department, this was their equipment. It could remember, if I recall correctly, about two lines of type. Once those two lines were printed out on clay-coated paper, the next two lines could be input and so on. Once the entire block of type was printed out, the paper was sprayed with a fixative to prevent smearing. From there, it was run through a waxer, which deposited a thin coat of hot wax onto the back of the paper; it was then cut out and pasted onto the "mechanical", a complete image of the ad, for example. It was covered with a flap of tissue paper, and sent to the printers to be photographed and then the image was used to make a printing plate for the press.
Fonts could be changed by changing the "ball", a spherical metal object with 3-dimensional letters on it, like those in a manual typewriter.