There are two types of properties associated with text:

Font Properties

The CSS syntax to specify fonts is:

tag { font-family: font 1, font 2, font 3, font 4, font 5, generic collection; }
 
body { font-family: "The Monkies Ate My Soul", Tekton, "Jazz Let", cursive; }

In developing pages and sites, designers often get carried away when they learn the syntax for specifying the font to be used.

"Wow", they think... "now my pages will look this way for everyone".

But, unless the user has The Monkies Ate My Soul installed on their computer, the browser will default to the next font, Tekton. If Tekton is not available, it will default to Jazz LET, and so on until it gets to the generic collection name, in the case above, cursive. MUCH time can be spent thinking about this when planning your design.

Default Fonts

The simplest way to specify fonts is to use one of the generic collection names. Every device can display fonts from these default collections, so if you know you want a sans-serif font for your headers, but don't want to hassle with all the options for all the platforms, you can just write the CSS specifying a default collection sans-serif. All elements that descend from the BODY (in the example below) will also inherit this same font choice unless you specify something else.

body { font-family: sans-serif; }

When specifying a list of fonts, you should always include a generic font name at the end of the list.

body { font-family: "The Monkies Ate My Soul", Tekton, "Jazz Let", cursive; }

Here is a list of the generic collection names available:

serif
sans-serif
monospace
fantasy
cursive

Fonts Available on Macs and PCs

There are LOTS of fonts available. The problem is that all web-based type use fonts installed on the user's computer. You can't be sure that all Mac users, for example, will have the same fonts - some are installed with software packages, some may be download, some may be obtained illegally (gasp!), who knows???!!

To avoid problems, developers should stick to fonts which are common on most platforms. Here is a list of (relatively) safe (but boring) fonts. Also check the Resources page for links to other resources that help with this question.

Arial Webdings Tahoma
Arial black Georgia Times New Roman
Arial Narrow Ompact Trebuchet MS
Century Gothic Monotype Verdana
Comic Sans MS Palatino Franklin Gothic
Courier New Symbol  
By the way, the font name must be spelled correctly for it to work correctly. While the names of fonts are NOT case sensitive, it is a good idea to always consider and follow case sensitivity... IDs and classes are case sensitive, so it is good practice to get in the habit of considering that every named "thing" in web development is in fact case-sensitive!

When creating font lists, place the name of the preferred font you prefer first. Follow it with other acceptable fonts and always end the list with a generic font!

Note that if the font has more than one word in the name, that name should be inside quotes! If you leave out the quotes, the user agent may ignore that particular font. For embedded and linked CSS, either single or double quotes will work. You can mix Macintosh and Windows fonts in a declaration so that your pages will look pleasing on both platforms.

The default generic fonts should never be quoted.

body { font-family: Arial, Geneva, "Century Gothic", sans-serif; }

In the example above, the font will be set to Arial (on a PC) and Geneva on a Mac if it doesn't have Arial installed. This setting will be inherited by all the other tags because the BODY tag is a top-level element. So, with one line, you have set all the fonts in your entire document!