Who is Steve Ditko?
Well, since he's credited as the co-creator of Spider-Man in the upcoming movie (perhaps you've heard of it), a number of reporters have been asking that question. They're discovering what comic book fans already know: Ditko doesn't talk. To anybody. But what little is known about him has been assembled in one place for general audiences by the LA Times.
You won't find an overview of his work there: Try here. (It's an ugly page -- sorry -- but it's crammed full of images and information.) Ditko's principles and personal tastes have made him paradoxically influential and obscure. His biggest hit was Spider-Man, and only he knows why he left the title in 1966, never to return. Stan Lee was probably the only scripter who could have brought Ditko into the mainstream, however briefly.
But boy, those first four years...
LATER: In the New York Times (link requires free registration), Stan Lee speculates on the reasons for Spider-Man's popularity. Mark Evanier warns you not to believe the story about Amazing Fantasy having already been cancelled when Spider-Man appeared in #15; I'll express skepticism when Lee claims ""Spider-Man" was the first comic book to make extensive use of "thought balloons"".
I should also tell you, I who have no financial interest in it, that you can own all of Ditko's Spider-Man stories for about $30 if you buy The Essential Spider-Man volumes one and two.