There are two elements to this book: the gentle satire and observation of the wealthier classes in Barcelona, their activities, politics and lives; and the crime thread, when a politician's wife is found poisoned, and two unconventional twin investigators are charged with solving the crime.
I found the crime story unconvincing. There was no real detecting involved. The two amiable investigators wandered about following and talking to and, luckily bumping into significant characters. And the final denouement of the murderer was weak and improbable, as was his careless method.
The description of the atmosphere and characters surrounding the narrator's family is warm and funny, as are other elements - such as the survey that finds that out of 500 Spaniards polled, 482 have never read Don Quixote, and the same number would never admit to that in public.
The part of Barcelona society dealt with is that part living mostly "North of the Diagonal," the Catalan, more well-heeled sectors of the city. There is nothing wrong with this choice of course, but as a portrait of Barcelona - which it doesn't set out to be, I acknowledge - the book leaves undescribed much of that vibrant city and its layers and atmosphere.
In spite of the modern setting, the murder-story seemed old fashioned to me in its lack of character depth and motivation, and it relied too much, as too many crime novels do, on lucky coincidences.
The translation is a curious mix of the up-to-date and out-of date idioms. There is the odd grammatical mistake too: "had broke" instead of "had broken", for example.
"A Not So Perfect Crime" is a light read, and entertaining, but more for learning a little about the social habits of the characters than for understanding about crime and punishment in that complex city.
If you like some darkness with your crime, this book is not really for you.