In the previous example, I could instead have:

<xsl:template match="syllabus">
<xsl:apply-templates select="recommended-books"/>
</xsl:template>

<xsl:template match="book">
<p><xsl:apply-templates/></p>
</xsl:template>

When I add 'pamphlet' or 'article' elements to the children (i.e. siblings of 'book') I just add:

<xsl:template match="pamphlet">
<p><xsl:apply-templates/></p>
</xsl:template>

<xsl:template match="article">
<p><xsl:apply-templates/></p>
</xsl:template>

But it gets even better...