Display a field from a content type which is not displayed in the current node
I think you're looking for the node_load function.
Example:

function mytheme_preprocess_node(&amp;$vars) {
  // Load node with ID 123.
  $another_node = $node_load(123);
  // Format a date.
  $vars['another_node_created'] = format_date($another_node-&gt;created, 'custom', 'Y, m, d' );
}


Beware that node_load returns raw data from the database. While $another_node-&gt;created is a safe value to use, user entered data (eg. the title or body text) needs to be checked before you print it (eg. &lt;?php print check_plain($another_node-&gt;title); ?&gt;). Not checking raw data is a security risk for your site. See Handle text in a secure fashion for more info.