Peter B. Rysdale

In the novel The Secret Adversary, Peter B. Rysdale is mentioned by Tuppence.

Tuppence tells Albert that Peter Rysdale is an "oil king", whose emeralds had been stolen. She tells Albert that she is a detective investigating Mrs Vandemeyer, who is suspected of stealing the jewels.

Tuppence tells Albert this in order to gain his trust, and get him to help her get a place as Mrs Vandemeyer's maid. It is not stated whether Peter Rysdale is a real person, or if Tuppence made up the name in order to have a story to tell Albert.