Tamye Riggs, writing for Typekit:
PostScript’s biggest impact on publishing would be its most liberating element—computers and printers from different manufacturers would be able to talk to each other. […] With the magical combination of the Mac GUI, Adobe PostScript’s type- and image-handling capabilities, and the LaserWriter’s crisp 300 dpi output to plain paper and built-in AppleTalk networking scheme, the world of publishing was about to be turned on its ear.
Hard to imagine what using type was like before that magical combination:
From the 1950s through the mid-1980s, setting type remained a highly specialized skill, with operators trained in the use of one or more proprietary phototypesetting systems. It took a great deal of time to learn to use a given typesetter, as each manufacturer implemented its own unique coding scheme. By the mid-1970s, there were dozens of different phototype systems vying for market share.