The wiki has two levels of permissions for wiki spaces:

• Space level
• Page level

If you can navigate to a wiki space, you have permission to view that space.  If you can this page and any child pages in a wiki space, you have editing rights as well.

If you know there is another page, but you cannot see it, it probably has a viewing restriction (page level).  A page can be set to be viewed by only a handful of individuals, so only they can see it.  This page and any child page underneath it will be invisible to anyone not on the viewing list -- think of this as a member's only club.

If you believe you should see a page but cannot, ask the space administrator to add you to the page restrictions (under Tools > Restrictions).