This is a very frequently asked question.
I hate to beg, but...
would one of the knowledgeable and capable HTML book/intro/tutorial
writers research this issue and submit an answer to the WWW FAQ
Currently, that would be Thomas Boutell <email@example.com>
Basically, the options are:
server-side includes (see NCSA server doc)
cpp/m4/text preprocessor of your choice
<a href="included.html" REL=INCLUDE>...</a>
(we've got a student implementing this, by the way!
Real SGML Entities (tm)
Daniel W. Connolly "We believe in the interconnectedness of all things"
Research Associate, MIT/W3C PGP: EDF8 A8E4 F3BB 0F3C FD1B 7BE0 716C FF21