This article is from the Amiga FAQ, by Ignaz Kellerer with numerous contributions by others.
PostScript is a programming language designed to be used to describe printing on pages. Apple helped make PostScript popular by selling printers with built in PostScript interpreters. Many programs have evolved to produce PostScript programs as their output, making PostScript the lingua franca of printing. Until recently, in order to print a PostScript file, you had to have a relatively expensive laser printer. The development that changed this was the software PostScript interpreter. These programs allow your computer to interpret PostScript programs, and produce the matrix of dots to send to your normal graphics printer.
One of the benefits of PostScript is that it is resolution independent. What this means is that it can support the highest resolution of your device - and that you can reasonably preview PostScript on a low resolution screen.
There are two free PostScript interpreters for the Amiga. Post and Ghostscript. Post comes as an Amiga shared library along with front ends for previewing to the screen and printing. This structure allows others to write programs that can show PostScript images on screen. In fact, AmigaTeX uses Post's library to support incorporation of PostScript into documents. Ghostscript similarly comes in two programs, but not as a shared library. Ghostscript is the rendering engine, and Ghostview is the front end. Sources: Aminet (directorys `text/print' and `text/dtp'), Fish disk 669
The Amiga is able to use two different concepts of fonts. First of all there are the bitmap fonts. These fonts are created by drawing a letter pixel for pixel onto the screen. The advantage is that they look good at small sizes, but are not very good for printout. Also they don't look very good when you change their size. Therefore you have to recreate the font for each size. Second there are the vector fonts. They are created by curves which are stored as mathematical formula. This has the advantage that changing the sizes does not effect the output. But this only applies for larger sizes and print-outs. Vector fonts also use less memory.