Bodkin, M MacDonnell: The Capture of Paul Beck (1911);v1; 26 Feb 2020
 

"The Rule of Thumb" detective Paul Beck was popular in the Victorian and later era, a contemporary of Sherlock Holmes; unlike Holmes, he did not achieve cult status, and gradually disappeared from the shelves.

I have already posted the novel in which Paul Beck's son investigates a case, with a little help from his parents. This novel precedes that book. It has Paul Beck and Dora Myrle as private detectives on opposite sides of a fraud case. Later their interests converge....