Ruth Van Rydock

In the novel They do it with Mirrors, Ruth Van Rydock (née Martin) is the sister of Carrie Louise Serrocold and an old school friend of Miss Marple. She is an American socialite.

Ruth says that she is practically the same age as Miss Marple. However, everything "that money could do had been done for her--reinforced by diet, massage, and constant exercises". So, her face appears almost girlish at a slight distance, and her hair is "less grey than tending to hydrangea blue".

Ruth is described as cosmopolitan, coming to Europe every one or two years. She would rush from London to Paris, to the Riviera and back again, and would see her old friends wherever she was.

She has been married three times, each time to an extremely wealthy man. The resulting divorces left her a very wealthy woman.

Portrayals
In Murder with Mirrors (1985), Ruth van Rydock is not featured. Miss Marple is asked to go to Stonygates by Christian Gulbrandsen himself.

In the BBC 1991 adaptation of the novel which formed part of the Miss Marple series, Ruth van Rydock is played by Faith Brook. The portrayal is close to the original novel except that she and Miss Marple are not schoolmates. Miss Marple was some kind of "governess companion" for Ruth and Carrie Louise during a European tour. Another difference is that Ruth comes to Stonygates herself, and brings an old film showing herself, Carrie Louise, and Miss Marple as girls. In the novel, Ruth only appears at the beginning, when she asks Miss Marple to go to Stonygates. She does not go to Stonygates herself.

In the ITV 2009 adaptation of the novel as part of their Agatha Christie's Marple series, Ruth van Rydock is played by Joan Collins. Her role is larger than in the novel. She was at Stonygates and witnessed the fire in Carrie Louise's study. She then asks Miss Marple to visit Stonygates and look after Carrie Louise. Unlike the novel, she is also a trustee of the Gulbrandsen Foundation and together with Christian had noticed something odd about the accounts. When she learnt that Christian had been murdered, she drove up to Stonygates. When finally Carrie Louise learns that she might have been slowly poisoned, she gets upset with Ruth for not sharing her suspicions. The two sisters quarrel and Ruth drives off. Miss Marple comments that the two had always been good sisters as long as they kept an ocean between them.