Erle Stanley Gardner 
Double or Quits 

Dr. Hilton Devarest was a whiz at curing patients, but his private life was sick, sick, sick. He lived with a wife who was as warped as she was repulsive, a secretary who enjoyed fun and games with the doctor every morning before breakfast, a niece who believed nice girls finished nowhere, and a nephew whose only means of support was making women happy. Donal Lam and Bertha Cool got involved with the not-so-good doctor when he hired them to find some stolen jewels. But soon they were in the fight of their lives against a killer who thought murder was the best medicine, and was out to treat them to an overdose of death …