This was my second time reading this book, and I think I appreciated it even more on the second read. 

All those little comments and reactions by doctor Shepard that had seemed innocuous or perhaps only a little strange, took on new meaning and made you appreciate the cleverness of Christie's writing. And despite knowing that he was the murderer, having read this years before, I still found myself questioning my memory and how it could have been done, only for Christie to pull it into a neat little bow in the end.

 

Agatha Christie has not been dubbed the Queen of crime for nothing.