As has become obvious in the discussion and examples leading up to this section, three characters in source documents have very special meaning: the less-than sign (<), the greater-than sign (>), and the ampersand (&). These characters delimit tags and special character references. They'll confuse a browser if left dangling alone or with improper tag syntax. So you've got to go out of your way to include their actual, literal characters in your documents.[26]

[26]The only exception is that these characters may appear literally within the <listing> and <xmp> tags, but this is a moot point, since the tags are obsolete.

To include a special character in your document, enclose either its standard entity name or a pound sign (#) and its numeric position in the Latin-1 standard character set[27] inside a leading ampersand and an ending semicolon, without any spaces in-between.

[27]The popular ASCII character set is a subset of the more comprehensive Latin-1 character set. Composed by the well-respected International Organization for Standardization (ISO), the Latin-1 set is a list of all letters, numbers, punctuation marks, and so on, commonly used by Western language writers, organized by number and encoded with special names. Appendix F, "Character Entities" contains the complete Latin-1 character set and encoding.

Whew. That's a long explanation for what is really a simple thing to do, as the following example illustrates. The example shows how to include a greater-than sign in a snippet of code by using the character's entity name. It also demonstrates how to include a greater-than sign in your text by referencing its Latin-1 numeric value:

if a > b, then t = 0
if a > b, then t = 0

Both examples cause the text to be rendered as:

if a > b, then t = 0

The complete set of character entity values and names are in Appendix F, "Character Entities". You could write an entire document using character encoding, but that would be silly.