The title of the book invites readers to spend thirty days with the famous inspector - this is how many stories are included in it. Not all take place in Vigata, the Sicilian town where Montalbano lives and works. Some refer to events that occurred when he took his first steps as a police officer.

It is, therefore, thirty investigations, some quite strange, but considering the character of the inspector, they could not be different. The sample of crimes is vast: premeditated or accidental, staged, anticipated or simply fictional.

Sometimes Montalbano arrives in time, other times very late. Occasionally, human justice comes logically and timely to provide a solution, while at other times, revenge or guilt takes its own course. Sometimes, as is the case in life, there is no cleverness to explain the mystery of crimes and, more broadly, of human actions.

Each case leaves a feeling of satisfaction or bitterness, because there are also some stories where it would have been better for things to remain as they were, without a solution to the problem.

[Excerpt from the text on the back cover of the edition]