Node Prepare (or something) is stripping the HTML

I thought I was losing my mind -- I could make any kind of changes to the {theme}_bookreview_content function and only those changes that were outside of HTML tags would appear in the final view. I stumbled on this post: http://drupal.org/node/10522 which made some sense of what I was seeing, but I am not sure if that is the exact problem or not. I haven't tested this, dunno if it only happens when you try to theme the function. The URL above suggests that you can "implement hook_view()" which I'm sure is true, but I don't actually know how to do that.