My favorite criteria is when pieces of a work of fiction--a line or a moment--come back to you after you've read the work when you're doing something entirely different. And I don't know how to catalog that.Powells interview with Alice McDermott.
A teacher of mine in college once said you have to remember when you are reading history what halls were open to people and which were lighted. It stuck with me.Interview with historical spy-novelist Alan Furst.