Positive and negative aspects of meritocracy are evaluated, together with the difficulties of realizing it in practice. The notion and the theory of networks are recalled. White (fully legal, socially useful), gray (legal, but morally doubtful) and black (illegal) networks are distinguished. Various examples of networks are considered: the family, associations (cultural, religious, political, sports etc.), mason lodges (among the grey networks) including a deviant secret lodge as the P2 in Italy (the nature of which is illustrated), criminal clans and mafia-type associations (a synthetic history of the mafia is provided).