Doctor Who Profile: The Fourth Doctor
The Fourth Doctor can perhaps best be described as alien. After the very human Third Doctor and UNIT era, this new wide-eyed and unpredictable Doctor is a dramatic change and while each Doctor to this point is brilliant and clearly the smartest man in whatever room he enters, this incarnation is the first to embody that brand of genius that can keep any number of seemingly random threads whirling in their brain at a given moment, jumping between them at will and only later revealing to the rest of the room how they’re connected. He has a manic energy and bluster that seems endless as well as a penchant for bickering with or teasing his Companions, particularly Sarah Jane and Romana I and though he can be deadly serious, this Doctor is most likely to be found with a wide grin on his face and mad schemes percolating behind his eyes.