Robert Martin Klein, often credited as R. Martin Klein, is a Los Angeles, California-based voice actor prolific in anime dubbing. He has been active from the late 1990s to the present.
In earlier, non-union work, he was often credited as Bob Marx. He voiced 001 in the Sony Pictures English dub of Cyborg 009: The Cyborg Soldier, initially using the Marx alias before being credited under his actual name in season 2.