I read this book as a teen.  Reading it again last week felt like I was reconnecting with my old friend, Ms. Christie.  She was my favorite author for so many years.

While the plot twists and turns quite often, it is really not complex at all.  Sub-plots are virtually non-existant in this book where it seems they could have been created easily enough.  However, one redeeming quality of the book would be the thought provoking theme: unpunished murder.

My daughter read the book just before I did for our book club.  It brought back memories of theory after theory on the identity of the murderer, theories that changed almost with every page.  Abbie didn't guess and I don't think I ever did either.  Even this time, I forgot who exactly it was even though I remembered parts of the book. 

Could the lack of sub-plots be a result of flat characters?  Each person in the story acts exactly as one would expect of his "kind of person".  None of the characters seems to really be an individual beyond basic description.  Perhaps the story would have been  more complex if the characters had been more developed by the author. 

On the other hand, although the characters themselves generate little thought, the theme does trigger a review of the ethics involved in punishing murderers.  If the law is inadequate to reach certain murderers, does an individual have the moral right to mete out the penalty due?  I don't think so.  I don't think the Bible sanctions such actions. 

Agatha Christie has been declared the queen of the murder mystery genre and this book has been named among her best.  So, if a complex plot and well-developed characters are not an absolute necessity for you,  you might really enjoy the challenge to detect the criminal of this who-dunnit.  You might find yourself considering deeper topics than you would expect besides.