Understanding xsl:key

Hello,

I've got trouble understanding the proper use of xsl:key and the 
key() function. Here's my XML-File:

<booklist>
 <book>
  <title>
   <name>Design Patterns</name>
  </title>
  <author>Erich Gamma</author>
  <author>Richard Helm</author>
  <author>Ralph Johnson</author>
  <author>John Vlissides</author>
 </book>
 <book>
  <title>
   <name>Pattern Hatching</name>
  </title>
  <author>John Vlissides</author>
 </book>
 <book>
  <title>
   <name>Building Applications</name>
  </title>
  <author>Mohamed Fayad</author>
  <author>Douglas C. Schmidt</author>
  <author>Ralph Johnson</author>
 </book>
</booklist>

Here's the XSL:

 <xsl:key name="test" match="title" use="name"/>

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

 <xsl:template match="book">

  <xsl:if test="key('test','Pattern Hatching')">
   <node>
    <xsl:value-of select="."/>
    <xsl:text> -EndOfKeyValue-</xsl:text>
   </node>
  </xsl:if>

 </xsl:template>


Now, I'd expect the xsl:if to make sure only "name" elements that are 
children of "title" and have the content "Pattern Hatching"  are 
shown. Instead, I get ALL contents, including the author names; only 
the various "book" contents are (naturally) placed into single 
"node" elements.

Now, to make a long question short: WHY??? :)

Thanks,

Heiner
(who's read all "key"-explanations that he could find, but just seems 
to get something wrong)


 XSL-List info and archive:  http://www.mulberrytech.com/xsl/xsl-list