You can make a link to another wiki page simply by stating the name of the wiki page.  For example, the name of this page is MarkupInternalLink.

The name of a page has a special syntax known as a [[!-WikiWord-!][<UserGuide.FitNesseWiki.WikiWord]].  A [[!-WikiWord-!][<UserGuide.FitNesseWiki.WikiWord]] starts with a capital letter and has at least one more capital letter in it.  Between the capitals there must be lower case letters or numbers.  There cannot be two capitals in a row.

Thus:

|!c '''Wiki Words'''|!c '''Non-Wiki Words'''|
|!-BobMartin-!|Bob|
|!-RobertCecilMartin-!|hello|
|!-ObjecT-!|Object|
|!-NumbersLike123AreAllowedNow-!|Butnotlikethis123|

If you place a [[!-WikiWord-!][<UserGuide.FitNesseWiki.WikiWord]] in the markup text, but no such page exists, then you will see something like this on the page:

NoSuchWikiWord

If you click on the question mark it will create that page for you, and allow you to edit it.

If the link to other pages is long, such as the link to a page in another [[!-SubWiki-!][<UserGuide.FitNesseWiki.SubWiki]] like <UserGuide.FitNesseWiki.SubWiki, then the link can replaced with easier to read text by using this markup:

{{{[[text shown on screen][<LinkToOther.SubWiki]]}}}