A very enjoyable, lengthy mystery, with a cast of interesting characters, and a well-plotted story.
Annie Fuller lives in a large house in San Francisco in 1879, which she has inherited. She supplements her income by posing as a clairvoyant called Madame Sybil, in order to give advice to members of the public. She uses her ability to 'cold read' people, and her understanding of the financial markets, to give advice to business people and others.
When one of her clients dies, apparently by his own hand, Annie is convinced he would not commit suicide, and investigates the case.
I enjoyed this story, which I found detailed and convincing. Several possible suspects appear, and the conclusion is very satisfying.