“I am often asked is [my work] science fiction or fantasy and my answer is usually ‘Yes’.”

Ray Bradbury interview http://lists.topica.com/lists/gsn-newsday-list/read/message.html?sort=t&mid=911788456 March 23, 2005

"Elizabeth Hand on Mortal Love at HarperCollins (2004)

The Twilight Zone, "The Fugitive" (1962).
The Twilight Zone

Source: The Hero and the Crown

"A Conversation With Roger Zelazny" (8 April 1978), talking with Terry Dowling and Keith Curtis in Science Fiction Vol. 1, #2 (June 1978) http://web.archive.org/web/20070701010155/zelazny.corrupt.net/19780408int.html#2
Context: Yeah, the mythology is kind of a pattern. I'm very taken by mythology. I read it at a very early age and kept on reading it. Before I discovered science fiction I was reading mythology. And from that I got interested in comparative religion and folklore and related subjects. And when I began writing, it was just a fertile area I could use in my stories.
I was saying at the convention in Melbourne that after a time I got typed as a writer of mythological science fiction, and at a convention I'd go to I'd invariably wind up on a panel with the title "Mythology and Science Fiction". I felt a little badly about this, I was getting considered as exclusively that sort of writer. So I intentionally tried to break away from it with things like Doorways in the Sand and those detective stories which came out in the book My Name Is Legion, and other things where I tried to keep the science more central.
But I do find the mythological things are creeping in. I worked out a book which I thought was just straight science fiction -- with everything pretty much explained, and suddenly I got an idea which I thought was kind of neat for working in a mythological angle. I'm really struggling with myself. It would probably be a better book if I include it, but on the other hand I don't always like to keep reverting to it. I think what I'm going to do is vary my output, do some straight science fiction and some straight fantasy that doesn't involve mythology, and composites.

"How To Build A Universe That Doesn't Fall Apart Two Days Later" (1978)

It's the art of the possible. Science fiction is the art of the possible. It could happen. It has happened.
A Conversation with Ray Bradbury - Point Loma Nazarene University, Writer's Symposium By The Sea; April, 2001 http://www.cosmolearning.com/videos/a-conversation-with-ray-bradbury-2001-1131/

"A Conversation With Roger Zelazny" (8 April 1978), talking with Terry Dowling and Keith Curtis in Science Fiction Vol. 1, #2 (June 1978)