Paul Krugman, "for his analysis of trade patterns and location of economic activity". Now he becomes the first person outside the field of literature to win both the Nobel and Pulitzer Prizes, the acme of achievement in BOTH academics and journalism!
His contributions and the scientific background of his work can be found here and here.
Here is another short but superb biography of Krugman.
I have already posted three other topics on him or his work:
Income gap: widened or not?
Krugman @ Authors@Google (on his book, The Conscience of a Liberal)
Michael Moore in Economics Profession
Congratulations, Mr. Krugman!