A font is traditionally known as a complete set of all the letters of the alphabet, including associated ligatures, numerals, punctuation marks, and any other signs and symbols. A typeface, or simply face, is the name given to the design of the alphabet. Every typeface has a name, such as Goudy or Helvetica. The two words "font" and "typeface" are now used interchangeably ever since the transformation from hot metal typesetting, to phototypesetting, and finally to digital typesetting. Desktop publishing programs have a menu item labeled "font" to display a list of typefaces which confuses the terminology. A family is a set of fonts related to the basic typeface which may include italic, bold, and bold-italic plus several different weights and widths. The weights range from extra light to extra bold, and widths can range from extra condensed to extra expanded.

The two main font standards are Adobe PostScript Type 1 and TrueType. Choosing which type to use is a very important decision. It is a good idea to choose one type and stay with it. Do not mix PostScript with TrueType. Some typefaces are available in both types, but the visual characteristics of one font standard differs slightly from another. Because of this difference, using one type of font for displaying and proofing your work and then using a different font for printing can cause unpleasant surprises such as different letterspacing and line endings. Regardless of the standard you choose, make sure that your service provider uses the identical font produced by the same company that produced your font.

Adobe PostScript Type 1  

Adobe PostScript Type 1 fonts are the printing industry standard. Type 1 fonts have both a bitmap (screen) font for proper display on your monitor and an outline (printer) font that is used to create smooth type on a printer. Both the display and printer font are needed in order for the file to be output. Type 1 postscript fonts are the standard for imaging to any PostScript output device. PostScript fonts are PostScript language-based outlines, object-oriented vector graphics, that can be scaled to any size, and still remain sharp and smooth on any platform or output device.

A Type 2 font doesn't exist. There are Type 3 fonts, but they are of inferior quality.

TrueType

TrueType fonts work with both non-PostScript and PostScript output devices. However, when printing to a PostScript printer, TrueType fonts must be converted to a PostScript outline, and the quality of the resulting font depends on the quality of the conversion. They work well for designs that will appear on screen, such as Websites, and for cross-platform consistency, but for printing on a high resolution typesetter, you advised to use PostScript Type 1 fonts. TrueType was developed by Apple Computer and the Microsoft Corporation to replace bitmap fonts. TrueType fonts are just one file and can be identified by its icon with three A's on it. 

Multiple Master

The Multiple Master (MM) format is an extension of the Adobe Type 1 PostScript format. A MM typeface is basically one typeface family from which hundreds of customized variations, called multiple master instances, can be generated. An instance is a particular rendition of the font along a particular design axis, such as weight, width, optical size and style. MM fonts include several primary axes that you can use to create an almost infinite variety of font instances using the Font Creator. All multiple master fonts have MM after the typeface name, with the numeric values of their weight and width added to short axis abbreviations (i.e., MinioMM_578 BL 465 NO 8 OP).

Cross-Platform

Fonts do not cross over to another platform very well ( i,e., from PC to Mac). This is true even if you use Type 1 fonts. They have slightly different names so they are usually not recognized and will show up as missing fonts. Another problem is that special characters use different key combinations. For example, the PC has fraction keys and the Mac has ligature keys that produce something different on the opposite platform. The difference in the keys is one of the reasons why you should always send a hard copy of a file if it is to be output elsewhere.

Types

Serif typefaces have distinctive tails on vertical and horizontal lines. They are more legible at text sizes 14 points or less, so they are most often used for body text.

Sans serif typefaces do not have the serifs. They are used for headings, and subheads, but can also be used for body text.

Display type is used for headlines and should be used sparingly. It is very important to use the right font for your headlines because it sets the style or mood of what you are trying to say.

Script typefaces are used for formal pieces such as wedding invitations. NEVER set type in ALL CAPS using a script face because it becomes very difficult to read.