The fantastic characters that populate modern fantasy and science fiction movies have to take their initial form in someone’s imagination, long before the casting director, costumers and actors bring them to the screen. Usually, they first come to life in the mind of a concept designer. The more fertile that designer’s imagination, the more striking and memorable the character.
Iain McCaig is one of the leading concept designers in the film industry. His most recognizable work would be his character designs for the last three Star Wars films. He created the character of Darth Maul, was instrumental in creating the look of Jar Jar Binks (hate him or loathe him, you do remember him), and Queen Amidala, along with much of the costuming and designs for many other characters and creatures.
He has also worked on films like Hook, Terminator II, StarTrek VI, Peter Pan and Harry Potter and the Goblet of Fire.
His precise but fluid linework, excellent draughtsmanship and wild imagination make his concept drawings and paintings stand out.
There is a short bio here, an article on StarWars.com here, and an interesting report on a storyboarding workshop here. You can also probably turn up some interesting stuff with a Google image search.
One of the best places to see McCaig’s work is in the Art of Star Wars books: The Art of Star Wars, Episode I – The Phantom Menace, The Art of Star Wars, Episode II – Attack of the Clones and The Art of Star Wars, Episode III – Revenge of the Sith. I particularly recommend the volume for Episode I which has lots of McCaig’s character designs and many of his beautiful costume drawings (image and detail above).