This Christie book is a little darker than most. It was published in 1940 and Christie shows the fear of that time period. She has characters that are fascists and leftists. The economic fears of the time are tangible. In addition, Hercule Poirot is not quite as arrogant and is more subdued. He even questions himself, fearing that he is getting too old to properly analyze clues. I found the solution a little confusing and I am not sure how Poirot used his brain cells to solve the murder of his dentist.