<?php 
// continue.php
session_start ();
if (isset ( $_SESSION ['username'] )) 
{
	$username = $_SESSION ['username'];
	$password = $_SESSION ['password'];
	$forename = $_SESSION ['forename'];
	$surname = $_SESSION ['surname'];
	echo "Welcome back $forename.<br />
		 Your full name is $forename $surname.<br />
		 Your username is '$username'
		 and your password is '$password'.";
} 
else
	echo "Please <a href=authenticate2.php>click here</a> to log in.";
?>

Sessions neatly confine to a single program the extensive code required to authenticate and log in a user. Once a user has been authenticated, and you have created a session, your program code becomes very simple indeed. You need only to call up session_start and look up any variables to which you need access from $_SESSION.