"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.