I won't say I'm a Christie expert. I won't say I'm a Christie connoisseur. I won't even say I'm a Christie fanatic. What I am is an occasional Christie reader. I definitely have not read everything she's ever written. I haven't even finished all the books containing either Marple or Poirot. I have, however, read enough to know that I usually enjoy her stories. This was not one of them.
In the dedication Christie writes "You (James) complained that my murders were getting too refined- anaemic, in fact! You yearned for a 'good violent murder with lots of blood'. A murder where there was no doubt about its being murder! So this is your special story- written for you. I hope it may please. Your affectionate sister-in-law, Agatha"
What this tells me is Christie was writing this to please the audience, rather than herself, and it shows. The characters weren't nearly as complex as others and were somewhat choppy. I kept losing track of when Colonel Johnson was present for the action and when he'd gotten off somewhere. Which is pretty sad since he's the one who drags Poirot into the investigation in the first place. The characters kept getting churned up in my head and if Christie hadn't had people harping on aspects of the others personalities I would probably have completely lost them. Needless to say, with this much confusion going on and the clues not nearly as precise, if subtle, as I've seen from Christie, this book was really hard for me to get through.
The ending, which I won't give away for those people like me who hadn't gotten to this book yet, was bewildering in so many ways. Was there three twists or four, and when did we see the clues that point to the actual murderer? I'm sorry to say, this whole book lacked cohesion and coherency for me, which was disappointing. Christie does much better work when she's only writing to please herself, not fulfill another's expectations.