The Door Into Infinity by Edmond Hamilton, Science Fiction, Fantasy (Paperback) (ISBN-13: 9781463800963)

"Where leads the Door?"

"It leads outside our world."

"Who taught our forefathers to open the Door?"

"They Beyond the Door taught them."

"To whom do we bring these sacrifices?"

"We bring them to Those Beyond the Door."

"Shall the Door be opened that They may take them?"

"Let the Door be opened!"

Paul Ennis had listened thus far, his haggard face uncomprehending in expression, but now he interrupted the speaker.

"But what does it all mean, inspector? Why are you repeating this to me?"