why TITLE, not TITLE?

Recently, I've been playing around with a DTD-driven parser, and
noticed that it would break when there wasn't a TITLE element
in the document.  This was a little suprising, since a lot of
HTML documents don't have this TITLE tag, and I figured it
was optional.  I was suprised after checking the HTML3-2 DTD that
it is required conten of the HEAD element.  Thus my question, 
'Why is it that TITLE is a required member of the HEAD element?'

This means that:
Hello World
is invalid HTML, while 
Hello World
is valid HTML.  Making TITLE optional (e.g. TITLE? in the element
content model for HEAD) doesn't seem to create any ambiguity in the
grammar,  and makes simple text documents and existing HTML
documents w/ no TITLE tag HTML-compliant.   The above 'Hello World'
document becomes:

Finger me for my pgp public key
Today's random buzzword: plug-and-play dilbert

Received on Thursday, 8 May 1997 21:05:48 UTC