Kill As Directed — Ellery Queen

A desperate doctor finds that crime is the best cure for poverty -- unless it gets him killed -- in this novel from the legendary mystery author.

Harry Brown is a good doctor, but he doesn't know the antidote for the poison that has coursed through him for 2 decades -- the poison of envy. Ever since his days in prep school, when this scholarship student looked longingly at the fine clothes and expensive cars showered on the other children, Dr. Brown has been desperate for wealth. Becoming an MD was supposed to be his ticket to the good life, but after 2 years' practice, his savings are nearly exhausted and the good doctor is staring poverty in the mouth. It will take a miracle to save him -- but the one that arrives could get him killed.
 
Hired as the private physician for millionaire Kurt Gresham, Dr. Brown is horrified to learn that his new employer is a heroin kingpin. But the money is good, Gresham's wife is beautiful, and Brown would rather be dead than poor.