The title of What's Bred in the Bone is taken from an old English proverb: "What's Bred in the Bone will not Out of the Flesh." In a prologue to the novel, Simon Darcourt is explaining to Arthur and Maria Cornish why he is having trouble writing the official biography of Arthur's uncle, the late Francis Cornish, for the Cornish Foundation. Darcourt has discovered that he doesn't know who Cornish was. The verifiable facts "don't add up to the man we knew." Two spirits, the Lesser Zadkiel (the Angel of Biography) and Maimas (Cornish's personal daimon while he lived) have been observing the proceedings and decide to review the record of the life of Francis Cornish. What follows this prologue is that record, interspersed with brief dialogues between the two spirits on the development of Francis' character. The record is divided into two sections: "What Was...