Thrones, Dominations an incomplete Dorothy Sayers novel! Of course completed by Jill Paton Walsh with wonderful flair. This one begins soon after Harriet Vane marries Peter Wimsey. It fits perfectly into the two short stories that Sayers wrote about the Wimseys. Those are set in the future — one on the night that Harriet Vane gives birth to a child and another five years later. Both of these stories can be found in Striding Folly.
