DM: Visualization

[Sandra Poprawski]

Dear ladies and gentlemen,

I am a student of the University of Karlsruhe and I am interested in
getting some information about data mining or KDD in general.
These are my questions:
(1) What is the difference between data mining an KDD (knowledge
discovery of databases)?
(2) Are there any companies which take part in this list of discussion
and use special tools for visualization of large databases ? What kind
of tools are there or what else do you prefer for presentation ?
(3) Are there any other systems than VisDB existing (that's the one 
I'm
working on)?
(4) Does anyone know good literature about visualization in general?

I would be very glad if my questions will be answered soon!
Thanks!

Sandra Poprawski