Greg's Hack is a tiny extension that anti-aliases most of the text on your Mac's screen. In other words, it uses shades of gray to blur the jagged edges of bitmap fonts. Anti-aliasing makes tiny text legible and large text smoother. This process requires either PostScript or TrueType fonts and a monitor capable of displaying at least 16 grays. It looks best at high screen resolutions, and since anti-aliasing is processor intensive, a Power Mac is recommended.