Hi Evangelos,<br>I own a copy of the User's Guide and have verified that the chapter about VTK FIle Formats and the online PDF documentation are the same. Anyway, the User's Guide is the perfect book if your aim is getting productive quickly with the main VTK's modelling and visualization classes. If this is your case, I strongly suggest that you buy the book.<br>
<br>Best Regards<br><br> Luca <br><br><br><a href="http://www.kitware.com/products/vtkguide.html">http://www.kitware.com/products/vtkguide.html</a><br><br><br>