Used to add content to the single book page.

Example:

/**
 * Add text after the book information
 *
 * @param int $post_id
 *
 * @return void
 */
function add_content_after_novelist_info( $post_id ) {
	?>
	Your text or HTML here.
	<?php
}

add_action( 'novelist/book/after-content', 'add_content_after_novelist_info', 20 );