The function behind the $node object is node_load(). This brings the $node object into play within your node.tpl.php template file and gives you the ability to display any variables from the node. Drupal handles everything behind the scenes -- access permissions, attached taxonomy, attached files, meta information, and more -- and hands you the gift wrapped object. In addition to the core variables, the node object also includes any added variables, such as CCK fields.
