This latest outing for Commissario Guido Brunetti concerns themes of population: immigrants into Western Europe, both adults and babies - and the very different attitudes of society to them. Events unfold when Brunetti is woken in the early hours of the morning to be told of a raid on a Venetian house by the Carabinieri, the Italian military police. During the course of the raid, the householder, a paediatrician, has been injured and the young child of the family has disappeared. As usual, Brunetti has to tread delicately, especially when he observes that his boss, Patta, is involved in some unknown way.

During the course of investigating this messy crime, Brunetti realises that the child was adopted, which leads him and Signorina Elettra, Patta's extraordinary assistant, to some duplicity to investigate the practices of a clinic in Verona. Elettra remains an enigma, however, although the character of Brunetti's colleague Vianello comes into focus - and seems to be more than professionally interested in the multi-talented Elettra.

Vianello has been following his own investigation into what he thinks may be a scam by a group of pharmacists, whereby they claim money for making hospital appointments for non-existent patients. On top of this, Brunetti gets involved in a right-wing political party, using his father-in-law as a way to gain its leader's trust.

All these events give the author plenty of opportunity to provide insightful comments on the Italian, and wider, social and political scene. Although she achieves this goal with her usual dexterity and sharpness of touch (I particularly liked Brunetti's realisation about the pornographic magazines), I felt that this book did not gel as well as some of Leon's previous mini-masterpieces, perhaps because there are too many unconnected elements. I sensed a slightly mechanical treatment of Brunetti's colleagues and the police operations. The Carabinieri aspects were particularly disappointing, and peter out.

As ever, the domestic interludes between Brunetti and Paola, his wife, are a delight. She does not cook in much detail in this book, but I was relieved to discover that one reason she is able to be such a paragon is that she has only four hours teaching commitment a week.

Ultimately, I found the mystery aspect of the book quite weak. There are too many strands of plot, few of which reach a rounded conclusion. Donna Leon's books are always interesting just because of what they convey about the minutiae of life in her chosen setting, but this particular episode is somewhat pale compared to her best.