Do you like mystery novels like Agatha Christie's?
oh I love mystery novels but I don't know much about those
She wrote over sixty detective novels. She was extremely popular in earlier generations. 
what was so good about them compared to other stuff at the time?
People just liked the mysteries in her books, I believe, and trying to figure it out. Hercule Poirot was most of the most famous characters of the time. 
oh cool. any movies based on her books?
Yes, some of her works were made for the television. For instance Agatha Christie's Poirot is a tv series about her work that aired from 1989 all the way until 2013! It was very popular.