When we were living in Colorado there was snowfall. Our cat — I’m a cat man — wanted to get out of the house so I opened a door for him but he wouldn’t leave. Just kept on crying. He’d seen snow before and I couldn’t understand it. I kept opening other doors for him and he still wouldn’t leave. Then Ginny said, "Oh, he’s looking for a door into summer". I threw up my hands, told her not to say another word, and wrote the novel "The Door Into Summer" in 13 days.