Here are 2 solutions:
Using Tag titles
<?php
switch( single_tag_title( '', false ) ) {
case 'Books' :
include 'tags/books.php';
break;
case 'Tables' :
include 'tags/tables.php';
break;
default :
break;
}
?>
Using tag slugs:
<?php
if ( is_tag( 'books' ) ) {
include 'tags/books.php';
}
else if ( is_tag( 'tables' ) ) {
include 'tags/tables.php';
}
?>