If I understand correctly, all the source code that comes with the book Windows Game Programming for Dummies is released under the GNU General Public License and the software that comes with the book has its own EULA. But I do not see the GPL anywhere on the CD. These questions are theoretical right now, I'm just being curious. First off, does anyone know if the GPL is the right license? Assuming it is... Can I distribute the games and the GPDUMB library freely? Can I use and abuse the source code? Can I freely distribute modified games and/or games using the GPDUMB engine? Can I sell modified games or a modified engine? Can I sell the games unmodified or the engine unmodified? And of course I have to give credit to the creator, right? Do people sell modifications to games like half-life and quake? Because it seems like they are mostly given out freely. How about this "contest" about underworld. I couldn't find the entries on the xgames3d.com? Anyone done anything with this... it doesn't seem to be going on right now, but it's supposed to go until 2005.