chapters, prefaces, and appendixes all have a similar structure. They consist of a title, possibly some additional meta-information, and any number of block-level elements followed by any number of top-level sections. Each section may in turn contain any number of block-level elements followed by any number from the next section level, as shown in Example 2-2.

<chapter><title>My Chapter</title>
  <para> ... </para>
  <section><title>First Section</title>
    <para> ... </para>
    <example> ... </example>
  </section>
</chapter>