VTK is an open-source software system for image processing, 3D graphics, volume 
rendering and visualization. VTK includes many advanced algorithms (e.g., 
surface reconstruction, implicit modeling, decimation) and rendering techniques 
(e.g., hardware-accelerated volume rendering, LOD control).

VTK is used by academicians for teaching and research; by government research 
institutions such as Los Alamos National Lab in the US or CINECA in Italy; and 
by many commercial firms who use VTK to build or extend products.

The origin of VTK is with the textbook "The Visualization Toolkit, an 
Object-Oriented Approach to 3D Graphics" originally published by Prentice Hall 
and now published by Kitware, Inc. (Third Edition ISBN 1-930934-07-6). VTK has 
grown (since its initial release in 1994) to a world-wide user base in the 
commercial, academic, and research communities.
