It's also clear, from the same essay that the fictional city is as a lovingly wrought secondary world creation as any that has graced the pages of a three volume epic fantasy. The police procedure used by McBain's cops is closely modelled on actual American procedures (of the time) explaining why the city maintains a sense of reality despite being entirely imaginary.
Heroes who work for a living
It's by making the extraordinary skills of a spy ordinary that Deighton highlights what we often overlook - how extraordinarily skilled many of the people around us our. Not just the obvious candidates, the doctors, nurses, electricians but the less obvious geniuses like crane drivers and health inspectors. I wanted Peter to be like a Deighton spy, competent (most of the time) in an understated way.
London: The Biography by Peter Ackroyd
The role of this book must be fairly self explanatory.
Randall and Hopkirk: Deceased