The Man Behind the Face
Codd has, hands down, the best and most intense stare in all of computer science history. He also looks a hell of a lot like that guy from Monty Python, but probably more importantly, he was the creator of the relational model. A theory of data management, the relational model was used as the foundation for relational databases.
Working for IBM in the 60's and 70's, Codd experienced a lot of pushback on the implementation of his theories. To counter, Codd went directly to IBM’s customers, showed them the value of his approach, and in turn, those customer’s pressured IBM into ceding to Codd’s methodology.
Check out Edgar Codd's Wikipedia page for a thorough description of his accomplishments and contributions.