Arthur Tyler III was an American entrepreneur. He was Pierre-Yves Dudoin's roommate at Oxford College, graduating with fellow classmate Christine Holland. They began a rivalry as to who could be the first privately-funded man in space.
In 2001, he accelerated his efforts due to him being diagnosed with an inoperable tumour and not knowing how much longer he had to live.
He was taken to a Kulan spacecraft and pled the Council of Three not to invade Earth. When Fitz Kreiner and Anji Kapoor caused the ships in the Kulan fleet to fire on each other, Tyler and the Eighth Doctor escaped from the Council chamber and found Fitz and Anji. To allow the others to get to the TARDIS, Tyler pulled the pursuing Fray'kon into an airlock and ejected them into space, killing them both. (PROSE: Escape Velocity)