On their website, the WGA has a terrific series of interviews called The Masters. In this one, Dennis Faye interviews Carl Reiner:

A look through Reiner’s resume shows that he’s been juggling scores of projects for over half a century, from his early work writing and performing for Your Show of Shows; to creating the Dick Van Dyke Show; to writing and/or directing Steve Martin’s early movies, including Dead Men Don’t Wear Plaid and The Man with Two Brains [both co-written with George Gipe and Steve Martin]; to his innumerable plays and novels, including last year’s novel Just Desserts: A Novellelah and his current writing project, a one-act play called Shakespeare was Wrong.

Some highlights:

What’s your creative process when you write?

I start with a blank page, and I put a line on it. I’ve done this a lot. I just put a line down, anything. And then I ask questions about it. The best example was a book I wrote called All Kinds of Love. I remember, from nowhere, I wrote the line – and I had nothing in my mind – I wrote, “He didn’t realize that hiring the Japanese tutor would have the impact in his marriage that it did.”

Now, that’s a funny line. I said, “Who is this guy and why is he studying Japanese?” Maybe he had to go to Japan sometime. “Why did it impact his marriage? I worked it out that he hired a man, but it turned out to be a Japanese woman who was very pretty and his wife got jealous. And it went on like that and became a rather good book.

I’ve done that a few times. I’ve certainly done it with short stories.

That would certainly be a good writing exercise for anyone.

Yeah, get yourself a premise you can ask questions about and then answer them.

This speaks to the genius of the man as we see what's at the very core of his writing instinct: curiosity. He puts something down, then asks questions. You follow your curiosity into the characters and through that into the story. That is the very essence of what I call prep-writing and that is the basis of all good writing.

For more of the interview, go here.