A Holiday for Murder

This is a bit of an anomaly among my Agatha Christie paperbacks - I bought it new sometime in the early 80s, but didn't open it for at least 30 years.  It's a pretty standard Christie - a rich, unpleasant man invites his family (including a never-met granddaughter, the offspring of his late, estranged daughter) to his remote estate for Christmas and dies violently in a locked room.  Everyone had a motive, everyone had opportunity, everyone had an alibi, and Hercule Poirot just happened to be visiting the local constabulary.  Throw in two impostors and a romance, and you've got an average Christie.  More diverting than engrossing, I'd put this in the beach read or commute book category.  You'll enjoy it, but it's not going to take up too much of your brain.