[support] hook_block Headache

[Fred Jones]

I am failing to get hook_block to work in D6 so I tried reducing my
code to the very simplest and it still fails. I copied code from
http://www.packtpub.com/article/creating-our-first-module-using-drupal6-part1
and now have nothing more than this in my module file:

<?php
/**
 * Implementation of hook_block().
 */
function mymod_block($op = 'list', $delta = 0, $edit = array()) {
   switch ($op) {
    case 'list':
      $blocks[0]['info'] = t('Goodreads Bookshelf');
      return $blocks;
    case 'view':
      $blocks['subject'] = t('On the Bookshelf');
      $blocks['content'] = t('Temporary content');
      return $blocks;
  }
}

When this module is enabled, no blocks appear on my site whatsover. If
I disabled it OR just remove that code, then the blocks appear.

This is bizarre, no?