Show Custom Taxonomy Title

You can use single_term_title():

<h3><?php single_term_title(); ?></h3>

To hide it if there are no posts, use the if ( have_posts() ) : function:

<?php if ( have_posts() ) : ?>
    <h3><?php single_term_title(); ?></h3>
<?php endif; ?>

If not an archive, you can use get_term_by() to get the term object for the term and then echo the name:

$term = get_term_by( 'slug', 'book-1-chapter-1', 'book' );
?>

<h3><?php echo $term->name; ?></h3>