Book suggestions? 10 pts for which I choose!! :)?

So, which books would I like if I liked "And Then There Were None" and "Murder In The Calais Coach" by Agatha Christie. It or they can be by her, or some other author, and could you please tell a little about the idea of the book, not too much but the basic idea, and why you think it is good, or why I'd like it :)