I am unable to invoke the fields individually in a book module. I tried the following:

<?php print $node->content['body']['value'];?>
<?php print $node->field_level1[0]['view'];?>
<?php print $node->field_level2[0]['view'];?>
<?php print $node->field_title[0]['view'];?>

Nothing is being printed. What could be the reason? please help. I have overriden node-book.tpl.php and am calling these fields within it.
thanks
Navs