why doesn't the_content() work in this {single-custom_post_type.php} page?

Question

This code is from my page single-publication.php.

It outputs the relevant custom fields etc (here wrapped in template tags), but the_content() won't output the post content. I've resorted to using $post->post_content (which works), but the mystery remains:

<div class="publication-info">
    <?php printf("<h2>%s</h2>", get_the_title() ); ?>
    <div class="publication-meta publication-credit"><?php the_publication_credit(); ?></div>
    <div class="publication-meta publication-date"><?php the_publication_date(); ?></div><br />
    <div class="publication-blurb" style="font-family:sans-serif;"><?php echo $post->post_content; // the_content() doesn't work. Why not? ?></div>
</div>

What's going on here?

EDIT: I was driven to ask this question because I believed - mistakenly, as it turns out - that $post working and get_the_title() returning a title were an ironclad sign of being inside the loop. But apparently this is not the case. cf Codex on The Loop (second para) and Codex on get_the_title() (parameter list). Can anyone explain?

Answer 1

Some post-related data is not available to get_posts by default, such as post content through the_content(), or the numeric ID. This is resolved by calling an internal function setup_postdata(), with the $post array as its argument:

<?php
$args = array( 'posts_per_page' => 3 );
$lastposts = get_posts( $args );
foreach ( $lastposts as $post ) :
  setup_postdata( $post ); ?>
    <h2><a href="<?php the_permalink(); ?>"><?php the_title(); ?></a></h2>
    <?php the_content(); ?>
<?php endforeach; 
wp_reset_postdata();
?>

See Access all post data

Answer 2

There's a good chance your HTML is not included in the loop. Make sure your code looks like this:

if(have_posts()): while(have_posts()): the_post(); ?>

    <div class="publication-info">
        <?php printf("<h2>%s</h2>", get_the_title() ); ?>
        <div class="publication-meta publication-credit"><?php the_publication_credit(); ?></div>
        <div class="publication-meta publication-date"><?php the_publication_date(); ?></div><br />
        <div class="publication-blurb" style="font-family:sans-serif;"><?php echo $post->post_content; // the_content() doesn't work. Why not? ?></div>
    </div>

<?php endwhile; endif;