putting <x> ... </x> around your list of books to get a well formed
document, then



<xsl:stylesheet 
  xmlns:xsl="http://www.w3.org/XSL/Transform/1.0">


<xsl:template match="x">
<xsl:apply-templates select="book/country[not(. = following::country)]">
 <xsl:sort select="."/>
</xsl:apply-templates>
</xsl:template>



<xsl:template match="country">
<xsl:value-of select="."/>
<xsl:variable name="c" select="."/>
<xsl:apply-templates select="//book[country=$c]/title">
 <xsl:sort select="."/>
</xsl:apply-templates>
</xsl:template>


</xsl:stylesheet>


bash-2.01$ xt book.xml book.xsl 

          Canada
     
          A book that is published in 2 countries
     
          A book that is published in 3 countries
     
          Mexico
     
          A book that is published in 3 countries
     
          United States
    
          A book that is published in 2 countries
     
          A book that is published in 3 countries
     bash-2.01$ 


David


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