<?php if ( get_post_meta($post->ID, 'ecpt_chapters', true) ) : ?>
<?php
$temp = $chapters_query;
$chapters_query= null;
$chapters_query = new WP_Query();
$chapters_query->query('post_type=chapter&order=ASC'); // category slug
$book_slug = basename(get_permalink());
?>

<?php if ( $chapters_query->have_posts() ) : while ( $chapters_query->have_posts() ) : $chapters_query->the_post(); ?>
<?php $chapter_parent = get_post_meta($post->ID, 'ecpt_chapter_parent', true);
    if ( $chapter_parent == $book_slug ) : ?>
    <li>
        <a href="<?php the_permalink(); ?>" rel="bookmark" title="Book: <?php the_title_attribute(); ?>"><?php echo get_post_meta($post->ID, 'ecpt_pretty_title', true); ?></a>
    </li>
    <?php endif; ?>
<?php endwhile; // end of the loop. ?>
<?php endif; wp_reset_query(); ?>
<?php endif; ?>