An odd, but very intriguing, book, Decoded is the first book by very popular Chinese author Mai Jia to be translated into English. From a writer's perspective it's a great example how rules are really just guidelines and the only thing that counts is what works.
The protagonist of the story is Rong Jinzhen (he also goes by various other names) who is an autistic savant -- socially inept, but an otherworldly talent at mathematics. We don't meet him until about a third of the way in. The first third is his family history starting a handful of generations prior. This could be an aspect of Chinese culture and the valuing of ancestors, but it also works to set up Jinzhen as a tragic figure. When we finally do meet him we never really get a story from his point of view. It all comes through the image of him as held by those around him. He gets minimal dialogue and very few scenes of him in action.
As a child Jinzhen starts out neglected, but is taken under the wing of a pair of Westerners. First Mr. Auslander, a servant of Jinzhen's family, looks after him and sees that he is provided for. Then a mathematician who is stranded in China during the war takes notice of his innate abilities and becomes a mentor. In time, Jinzhen is noticed by a government security unit and is sequestered in their compound, assigned to decode ciphers. He makes quite a mark in the field but eventually the stress of decoding, or possibly the expectations of the world, drive him insane.
The story is told via a narrator, who occasionally breaks the fourth wall, and his recitation of statements he had from those close to Jinzhen -- his boss, his wife, others around him. The tone of the book is that of a gentle fable. How much of that is due to the translation, I cannot say. I do know that Mai Jia's reputation in China is as a genre novelist, but this work, at least as translated into English, is more subtle and emotionally rich than a standard genre thriller. In fact, there really are no thrills to speak of, it is entirely cerebral.
I doubt there is a simple underlying theme the author was tracking. If there is it can only be that the pursuit of the unknowable (with ciphers as a stand in) that compels us also destroys us. Jinzhen experiences this directly and completely in his decoding work. Those around him experience it to a lesser extent by trying to known Jinzhen, who is himself unknowable. But there are other ideas in play. The notion of fate is strong from the outset -- Jinzhen is helpless in the face of genetic inheritance and political circumstance. Other ideas include the relationship between artistic creativity and analytics, and the ongoing memory and shadow of the Cultural Revolution which continues to hang over China today.
Should you read Decoded? Well, most of what I follow around the web seems to indicate that it is being marketed as a spy thriller. It's really nothing of the sort. If that is your expectation you will likely find it slow and unsatisfying. Mai Jia has done something very interesting though. He has written and accessible, superficially conventional, book that is in fact pretty far outside the box. If that sounds appealing you should give it a go. It is not intrigue, but it is intriguing.