Philip Wadler - Home page at http://homepages.inf.ed.ac.uk/wadler/
One of the principal designers of the HaskellLanguage and of GenericJava. He did research on ways to extend the classic HindleyMilner type systems.
Author of several introductory papers OnMonads (http://homepages.inf.ed.ac.uk/wadler/topics/monads.html) and on LinearLogic and IntuitionisticLogic (see IsFkkActuallyTrue).
Maintains a list of applications of FunctionalProgrammingInTheRealWorld and a GuideToFunctionalProgrammingOnTheWeb (http://homepages.inf.ed.ac.uk/wadler/guide.html).
Wears the most outlandish clothes ever seen on a greying Jewish guy.
except when he takes his shirt off -- ShaeErisson
which he does with predictable regularity -- a fresher student of his