3D Realms (legal name Apogee Software, Ltd.) is a publisher and video game developer based in Garland, Texas, established in 1987. It is best known for popularizing the shareware distribution model and as the creator of franchises on the PC such as Duke Nukem, and also the publisher of other franchises such as Commander Keen and Wolfenstein 3D.
While the company is known as "3D Realms", the legal name of the company is Apogee Software, Ltd. The name "3D Realms" was initially created as a branding label in July 1994 for use by Apogee which would be dedicated to just 3D games (as Apogee was then known for several styles of games). However, shortly after this, 3D games started to dominate the industry, and Apogee decided to direct its focus on this style of game; as such, "Apogee" was abandoned as a trade name in late 1996. In July 2008, however, it announced that the brand Apogee Software would be revived with new games, but licensed to an external company, Apogee Software, LLC.