"I enjoy, I suppose, the 'golden age' book. That's very much what I was trying to do in these books - to take that finite number of suspects, the genuine whodunnit style, but make it very contemporary, bring it up to date, and make sure this is a credible person with a credible back story for nowadays." (BBC)
When she, J.K. Rowling, says, ‘golden age’, is it a common noun for specific field’s golden era: in her context, detective stories being flourished? Or when you speak the phrase, do you have any special period in mind?