FAQ, 

> I want to group these books by attribute "type" e.g. looking like this
> 
> myshelf
>         some book
>         yet some other book
> yourshelf
>         some other book
> 
> I've been messing around with keys but I can't get the 
> desired result...

See <http://www.jenitennison.com/xslt/grouping/>.

Cheers,

Jarno - Dulce Liquido: Incubos

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