I read Destination Unknown for the 1954 Club, and it is really more of a suspense/espionage novel seemingly based on Cold War politics than it is one of her usual mysteries. It is also not nearly as effective.
Thomas Betterton is just the latest of a series of scientists and researchers who have seemed to drop off the face of the earth. Although his wife Olive says she doesn’t know where he is, Jepson and his colleagues in a labyrinthian government office building think he has defected. When Olive asks for permission to travel for her health, they decide to have her followed.
Hilary Craven has left England for Morocco in the hope that a change of scenery will lessen her despair after first her husband left her for another woman and then her only child died of meningitis. But it doesn’t help, and she soon is going from pharmacy to pharmacy collecting sleeping pills. She is about to take them when Jepson bursts into her room with an alternative. The plane she was supposed to take to Morocco has crashed. She missed it and got another one, but Olive Betterton was on it. Both women are physically similar and have red hair. Will Hilary take Olive’s place and hope to be contacted, to try to find out where the scientists are even though it’s likely she won’t survive this mission? She agrees.
Although there are some complicated strands to the plot, not only is the novel not a mystery but it doesn’t feature the deft characterization or humor that are usually part of Christie’s books. Not one of her best, I’m afraid.
whatmeread 
Agree with you on almost all points. I’m a Christie junkie, and this one seems to have been written to take advantage of the spy/Cold War trope–and, perhaps, to continue the unbroken string of yearly publications. It was interesting from an historical point of view, so that one can see how the spy novel was developing at the time, but, as you say, it had none of Christie’s deft characterization or trademark humor.
Yes, I think so.
I thought about reading this one for 1954 Club, but I think I’ll probably be reading it later in the year anyway for the Christie challenge I’m taking part in. I often find I enjoy the standalones more than the Poirot and Marple books, so I’m sorry to hear this one was disappointing!
Some of them are good.
Ah I tend not to love her spy ones so much as her detection ones. Shame!
I do like many of her spy novels, but I think this one is one of her worst.
I guess that means if I read another spy novel, at least I can expect it to be better.
Most of them have a core mystery in them, allowing Christie to draw on her strengths, while the espionage part can allow for some fun, but improbable adventures. So her good spy novels are fun, but her bad ones are among her worst works.
Well, this one isn’t horrible,but it’s not that great.