For want of a serif a reader was lost. It's true. People magazine published its first edition using a sans serif font to typeset the body copy. Despite the nascent fascination with celebrity, few people did more than scan the photos. The publishers quickly corrected that mistake.

Unfortunately, it's the same mistake I see repeated in many websites and printed matter. Writers untrained in the graphic arts are selecting fonts that appeal to them. They're selecting sans serif fonts, notably Arial (a knockoff of Helvetica that Microsoft contrived so they wouldn't have to pay licensing fees to the people who held the design rights for this popular font). They like the look. It seems contemporary.

The problem is that they aren't seeing the finished typeset piece the way that readers see it. Writers are evaluating their typeset text on the basis of an ill-defined, subjective value and ignoring the most important criteria – is it readable? It's an easy trap to fall into because it's easy to overlook readability when you have already read it, probably numerous times. It's your baby. You have it memorized.

You should be evaluating your typeset text from the point of view of someone who hasn't yet read it.

So, what's a “serif,” I hear you cry, and why is it so damned important? I'm glad you asked...

The earliest handwriting wasn't accomplished with a pen or a pencil. It was written with a brush. Now, anyone who has ever painted their living room knows that a brush leaves bristle marks at the end of a stroke. The bristles don't all magically rise together when you raise the brush, and the last ones leave traces of their late departure. There are two ways of preventing this. You may reverse the stroke and leave a blob at the end or you may pull the brush to the side. It's obvious that the first choice is unacceptable, it leaves a mess. The second choice leaves a nicely squared off end with a little tail in the direction that you pulled the brush. In typography, this little tail is known as a “serif.”

Every letter in a font is composed of “strokes.” There are “risers” and “descenders” as well as “bowls” and “ligatures,” “spines” and “stems.” There is no need for a serif where two strokes intersect. One stroke covers the other. However, any stroke that terminates without overlapping another stroke needs a serif.

Modern fonts created with phototypesetting and castings that didn't necessarily require a serif to square off the ends of strokes and designers began developing new font families without serifs known as sans serif. [“Sans” – French: without] 

Modern word processing programs usually come equipped with a wide selection of fonts, both serif and sans serif. It's a trap, one that I hope I can help you avoid.

Keep these simple rules in mind:

1. Always use serif fonts for body copy – anything more than a paragraph.
   
   
2. Use serif fonts for headlines and headings only – just a few words.
   
   
3. Choose no more than two fonts for any website or printed matter – one serif and one sans serif. Make sure they look good together (ask your wife or girlfriend for help in choosing them if you are of the masculine persuasion).
   
   

“But, I really like Ariel and no one ever complained before,” I hear you cry. 

I could respond by assailing you with my qualifications garnered from a former life as a designer and creative director, then tell you to sit down, shut up, and do as I say. Or, I could add another thousand or so words explaining why serif fonts are more readable. Then, using all bold and upper case type, pronounce like the voice of doom, “That which is readable is more likely to be read!”

The truth is, I'd rather keep this in the realm of friendly advice and stop now. I've grown bored writing this, probably as much as you've grown bored reading it.

Good luck, and happy typesetting.