And Then There Were None
In my opinion Christie's detectives, for example Poirot and Marple, are officious, pompous and insufferable. This book thankfully does not have one of these characters and thanks to that, might be Christie's best book. What's more, I think its possible for the reader to solve this mystery if they really put their minds to it. Great story.
On a meta level, I found the amount of casual racism interesting. Examples - "that was the damnable part about Jews, you couldn’t deceive them about money" and "natives don’t mind dying, you know. They don’t feel about it as Europeans do". I wonder if we could conclude from this that the average person in the 1930s spoke and thought this way. Also interesting is that this book was originally titled Ten Little Niggers, then re-titled Ten Little Indians (ie, Native Americans), and only later And Then There Were None. This probably reflects the change in society's attitude towards minorities.