" He had opened the book at random several times, seeking a sortes Virgilianae, before he chose the sentences on which his code was to be based. 'You say: I am not free. But I have lifted my hand and let it fall.' It was as if in choosing that passage, he were transmitting a signal of defiance to both the services. The last word of the message, when it was decoded by Boris or another, would read 'goodbye. "

― Graham Greene , The Human Factor