Is there a simple way to add user access on a page level? I'm still getting used to the way Drupal works, most of what I have read on adding User Level Security on a Drupal site seems to be either View based or by using a Module like Panels.  I am creating a site that is rather simple in structure, with some high level pages that differentiate out the content to different areas.  I am using Superfish to generate a drop down menu system at the high level, and underneath I have some content areas that will either contain only a few pages or one specific area that will have many.  I am also using shortened URLs to make site structure easier to manage, although in general it comes across as flat.  I may be wrong in thinking in terms of pages, and if I need to reconsider that for the site that's ok, I have only been using Drupal for the past 6 months but its a good fit as a CMS for the site I am working on.

The requirement is only for three types of Users - Admin, Group Leaders, and Members.  I'd like to give Group Leaders some access to pages for editing permissions, although mostly only at a second level or specific pages.  Members will have some editing rights but only on a few pages.  Group Leaders and Members will have access to content in one specific area, where I will have many pages, no one else should be able to get in.  Content pages on Member activities will be accessible by only those who have a login, those not logged in should ideally not see the links or not be able to access the pages.

With Drupal 7, and using the Bartik theme and some modules (Chaos Tools, Display Suite and Superfish for now) what is the best mechanism to be able to grant permissions to view and access content on only specific pages in the structure I have?  The site is still new, so if I have to make changes I'd like to do so now before it gets too complex.

Update:
Just to note in addition what happened.  I was looking for some sort of access that was simple to add in and allow me control on an individual node.  Content Access module gave me this in a way I can teach my Users to utilize.  Sorry if it seems a duplicate, I was looking for more of a description on what the modules did than I had seen before.
Well when you say page in drupal, it comes down to a lot of options. it might be a views page, a panels page, a page created directly with hook_menu().

So options:


If its a panels/views page, you already have permissions options there through UI in those cases.
Node and taxonomy term pages, have contrib modules that does this..Ankit's answer above lists out some.
If the page is a custom page defined bu hook_menu, you can employ '#access_callback' parameter to add a permissions function where you can return TRUE of FALSE based on check.


After restricting access to each page based on roles, these will be respected already when you add their links to the superfish menu.