In the early days, I was writing scripts for virtually all the books, and it was very hard to keep all the artists busy; poor little frail me, doing story after story. So I'd be writing a story for Kirby, and Steve Ditko would walk in and say, 'Hey, I need some work now.' And I'd say, 'I can't give it to you now, Steve, I'm finishing Kirby's.' But we couldn't afford to keep Steve waiting, because time is money, so I'd have to say, 'Look Steve, I can't write a script for you now, but here's the plot for the next Spider-Man. Go home and draw anything you want, as long as it's something like this, and I'll put the copy in later.' So I was able to finish Jack's story. Steve in the meantime was drawing another story.....Okay, it started out as a lazy's man's device...but we realized this was absolutely the best way to do a comic.....Don't have the writer say, 'Panel one will be a long shot of Spider-Man walking down the street.' The artist may see it differently; maybe he feels it should be a shot of Spider-Man swinging on his web, or climbing upside-down on the ceiling or something.
Stan Lee

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On the early days of work at Marvel Comics. Interview (1975)