> Until now, I thought that
> <xsl:value-of select="self"/>, <xsl:value-of 
> select="node()"/> and <xsl:value-of select="current()"/> 
> would print out the same values, but found out that this is not true.

They are completely different.

select="current()" (or select=".", or select="self::node()") selects the
context node.

select="node()" selects the children of the context node.

select="self" selects a child element called self.

> 
> It seems that current() prints out all the values including 
> its child...

current() doesn't "print out" anything. It selects a node. If anything is
printed, that's done by whoever it is that selects the node. For example,
<xsl:value-of select="current()"/> creates a text node whose content is the
string value of the current node (if it's an element, this will be the
concatenation of all its descendant text nodes); and if you choose to print
out this text node on paper, that's what you will see.

Michael Kay
http://www.saxonica.com/