These rules are not to touch the women of other men of honor; not to steal from other men of honor or, in general, from anyone; not to exploit prostitution; not to kill other men of honor unless strictly necessary; to avoid passing information to the police; not to quarrel with other men of honor; to maintain proper behavior; to keep silent about the Cosa Nostra around outsiders; to avoid in all circumstances introducing oneself to other men of honor (the introduction requires the presence of a third man of honor who knows both parties and who confirms membership in the Cosa Nostra by saying, "This is our friend" or "This is the same thing").

DEFINE: Cosa Nostra membership operates on a coded introduction ritual that avoids direct self-identification, sealed by a third man of honor's confirmation.

Diego Gambetta, The Sicilian Mafia The Busi…, loc. 731