David> I've never heard of machine learning technicques for classification by subject.
David> Is the work of the person you mentioned, Gerald Salton, available on the Web?
David> Or he the authour of a book? If you happened to know the name of the book,
David> or some way of finding it, I'd be very appreciative.
Here are some links if you want to read up on this. Salton's books are not
on the WWW (as far as I know), but the first link below is a book that has
a lot of the same material.
http://www.dcs.gla.ac.uk/Keith/Preface.html
http://www.cs.wisc.edu/~belew/MLIA.html
http://www.enee.umd.edu//medlab/filter/filter.html
However, if you are more interested in getting a system running quickly,
and you are on a unix platform, you might want to read about the "Harvest"
system. Their system can use text indexing engines such as Glimpse:
http://harvest.cs.colorado.edu/harvest/doc.html
http://glimpse.cs.arizona.edu/ghttp/
Good luck.
- Dave
-- David A. White, Visual Computing Lab, UCSD