My good friends at Princeton University Press have sent me what looks like a fascinating book, Codes of the Underworld by Diego Gambetta. The author is a sociologist at Oxford whose previous work includes a study of the Sicilian Mafia. The question he addresses here is how a group maintains the trust essential to its economic success when it consists of criminals. The subtitle is 'How Criminals Communicate' and just paging through reveals plenty of gleaming nuggets. For example, I'm looking forward to the section about the superb acting skills of mobsters. As the blurb says:

“People planning crimes can't freely advertise their goods and
services, nor can they rely on formal institutions to settle disputes
and certify quality. They face uniquely intense dilemmas as they
grapple with the basic problems of whom to trust, how to make
themselves trusted, and how to handle information without being
detected by rivals or police… …. [Gambetta] uncovers the logic of the often bizarre
ways in which inveterate and occasional criminals solve their dilemmas,
such as why the tattoos and scars etched on a criminal's body function
as lines on a professional résumé, why inmates resort to violence to
establish their position in the prison pecking order, and why mobsters
are partial to nicknames and imitate the behavior they see in mafia
movies. Even deliberate self-harm and the disclosure of their crimes
are strategically employed by criminals to convey important messages.”

Oh, and I love the cover, which features a painting by Michael Crawford.