The ideal way to learn about the software is from the book it is designed to
support.  You should be able to get the book from any local bookstore or from
our web page. The web page also contains some html reference pages for the
objects in vtk as well as a FAQ.

  The Visualization Toolkit, An Object-Oriented Approach to 3D Graphics
  by Will Schroeder, Ken Martin and Bill Lorensen.
  Prentice Hall, ISBN 013199837-4

For more information and a FAQ see our web page at
http://www.kitware.com/~martink/