By Agatha Christie
"Elspeth McGillicuddy had just witnessed a murder on the train passing hers. A woman was being strangled! But no one believed her except her friend Jane Marple. Fortunately, the old spintster Marple was surprisingly adept at solving criminal puzzles. The only problem was, where were she going to start, when there was no body, no motive and and no knowledge of the victim's identity?"
(Above taken from here).
I enjoyed this one a lot. But then, I already knew I was a fan of Agatha Christie's books. :)