USS Voyager's Emergency Medical Hologram, or Zimmerman, better known as The Doctor, is a character on the science fiction television series Star Trek: Voyager. The Doctor was played by Robert Picardo.
The Doctor is the central fictional character in the long-running BBC television science-fiction series Doctor Who, and also features in a vast range of spin-off novels, audio dramas and comic strips connected to the series.
The Doctor is a name of several fictional characters in the Wildstorm universe. There is always only one Doctor at any given time, who is the latest in a long line of shamans protecting the entire planet. Each doctor is as powerful as the sum of all preceding Doctors, each of whom was also as wise and powerful as the sum of all preceding Doctors, hence, each new Doctor is more powerful than his immediate predecessor.