A few weekends ago, I did a reading and signing at a library in San Diego. Afte...

A few weekends ago, I did a reading and signing at a library in San Diego. Afterward, a boy handed me a crumpled piece of paper bearing these words: Casey the Utterly Impossible Horse.
“What’s this?” I said.
“It’s the title of a book I thought you would like,” he said.
“Casey the Utterly Impossible Horse?”
“Yep,” he said.
“I wish I had thought of that title,” I said.
“Yep,” he said. “But then you would have to write the book, too.”
“True,” I said. “Utterly impossible.”
What I wanted to say (b...