I can still remember times when I launched my good old DOS map editor DETH (and later ZETH) for building my very first maps about 20 years ago. Times have changed and where DoomBuilder by CodeImp was one of the greatest heaps in the early 2000s, I would consider MaxEd's GZDoomBuilder as a similarly important milestone to the mapping community as it has been with it's original predecessor. The program is currently actively developed by its author and you can not only download it from the ZDoom thread but also report bugs and most importantly suggest new features. GZDoomBuilder supports any kind of sourceport and includes all those latest features for these ports, for example UDMF mapping in ZDoom and GZDoom, models and all the other crazy things. Mapping was never easier and faster, this is a promise. Enough the talk: Go get it and make yourself useful!