How to pitch a story if you don’t know where it's heading

On book proposals, featuring Tony in Broadmoor, This American Life, and how The Psychopath Test was nearly a boring book about neurology.

Hello! Today’s post was prompted by subscriber Andrew Lloyd, who asked the excellent question: ‘How do you put together a book proposal outlining the shape of a story when part of the fun is not yet knowing exactly which direction the story will go in?’