Death on the Nile; by Agatha Christie.

One of the most famous from this writer, not the least due to the spectacular film - the story does lend itself to a spectacular film, rather.

A beautiful young woman who is a rich heiress, with a brand new handsome bridegroom, setting out on her honeymoon - only, he had unceremoniously ditched his previous lover when he saw the beauty he married, and it so happened the two young women had been best friends, in fact that is how the couple had met.

Now, the spurned lover is haunting them on the honeymoon, she is there everywhere they can and do go, no matter how carefully they camouflage their plans. Finally they are on a cruise on the Nile together, and she joins the cruise just as they are congratualting each other. Now there is no escape.

And then begin the deaths...