Agatha Christie is one of the best selling authors of all time. Years ago—I'm not sure whether this is still true—it was said that she had outsold the Bible!
I know opinions vary widely, but I have been a fan of Agatha Christie's since grade eight when my english teacher—one of my favorite teachers—assigned us Christie's "The Murder of Roger Ackroyd," to read—and we got to watch the movie! It was great fun—we each had to try and guess who had committed the murder—and I've loved her books ever since.
Every time I read one of Christie's books I ask myself, "How did she do it? What was her secret, why are her stories so popular?" I think I must have read each of her books many times and one thing I noticed is that in both her Miss Marple and Poirot books she tends to include a romance.
I find that interesting and possibly revealing.