Tom A. Hall is a Wisconsin-born game designer and voice actor who, along with John Romero, John Carmack and Adrian Carmack, was a co-founder of id Software. He wrote the original story treatment for Doom and Quake, the latter being re-used from ideas he put forward prior to being fired from the company by Carmack over various disputes about the design of the game. Despite his departure, numerous elements of his documentation carried over into subsequent games by id (such as including secrets and teleporters in levels, the latter of which would be re-used as Slipgates in Quake), including the Quake games. The non-linear hub system he envisioned - and which was partly implemented in Doom 0.5 - can be found in Quake II.
After leaving id, Tom continued to work on video games with other companies, creating Rise of the Triad and Terminal Velocity with Apogee Software (both reusing ideas from his Doom Bible), and Anachronox with Ion Storm, a company he co-founded with John Romero after Romero's own departure. He voices several characters in the Deus Ex series, including Walton Simons, Howard Strong and Morpheus in Deus Ex, and Stan Carnegie in Deus Ex: Invisible War.