4th Doctor

Tom Baker played the part of the Doctor for seven long years, was the first Doctor to “make” it in America, and the first one whose tenure drew the attention of the censors—all aspects that make him still the definitive Doctor. After all, when the Doctor appears on the Simpsons, it is Tom’s incarnation that appears.
If this era of the Doctor could be characterized in a single way (and incidentally, it can’t, but let’s say it can) then it would be when the Doctor became a Gothic adventurer. The show had always been a little scary, but this is when it went from being exciting, action scary to conceptually scary. It tapped into ideas and dangers that were all very real and had implications beyond educating children about science, politics and the environment as it had done before.
Gothic horror is one of the best genres of story to explore morality and consequences, and Tom Baker’s Doctor did just that. One of the recurring themes in the Baker era was the way religion is used to manipulate and control people. To list just a few of the many great examples: (Some of these are accompanied by some good fan-made trailers. Thanks go to http://www.youtube.com/user/biggerbaddaddy)

Ark in Space
Before Alien ripped through into audiences’ psyches, this story explored the idea of human on a space station waking from deep hibernation only to discover that an alien being was using them to incubate and reproduce. It is claustrophobic, intense, and makes creative use of a new technology for the day (bubble-wrap.)





Genesis of the Daleks
The Doctor faces his oldest (and most symbolically evil) foe, the Daleks when he is sent back to their creation with the task of preventing their existence. It is the classic debate, would it be justifiable for someone to have killed the child Hitler if they had known what he would become. You could avoid the deaths of millions, but you would have to kill an innocent child.



Pyramids of Mars
One of the earlier stories linking Egypt and its ancient religions to alien intelligences that just so happen to also be extra-demensional and also satanic, or at least demonic. The Doctor is always in a good vs. evil battle, but not often do the stakes rise to the level of evil on a Satanic scale.



The Face of Evil
The Doctor ends up on a planet where he is worshiped as a god. How did the natives come to worship him, or even know who he was? An interesting look at how false religions come into existence.



Robots of Death
This episode does explores a few philosophical themes involving robots, the uncanny valley, race and such, but it is really one of the best of the bunch because it is a classic murder mystery that is well written, acted and designed.



Talons of Weng-Chiang
This story is pure entertainment. It is the Doctor Who version of a Holmsian mystery with Victorian London, Chinamen, an evil little ventriloquist dummy and giant rats in the sewer.



The Stones of Blood
On his quest to find the missing pieces of the Key to Time, the Doctor encounters a sect of pagans worshiping at an ancient stone circle. As it turns out, the group are being deceived by an alien and the stones are monsters that drink blood.



State of Decay
In a parallel universe, the Doctor visits a planet where the population are ruled by a group of vampires. The vampires use a religious system to maintain control and forbid the people from discovering the truth by forbidding reading and education.



Logopolis
Tom Baker comes to the end of his term when he saves the entire universe from destructive entropy that the Master has conspired to unleash.