Mario Renato Abram*, Marino Sforna** AIRS – Associazione Italiana per la Ricerca sui Sistemi, Torino 18-20 Ottobre 2007 *CESI RICERCA **TERNA In the last decades, the interactions between the infrastructures of a country gained increasing importance and consequently people started to acquire consciousness of their mutual interdependencies. This situation became evident in the last years when a number of great blackouts occurred in U.S.A. and in Europe, when large portions of the electric power system collapsed and pulled other infrastructures to collapse. A brief description of critical infrastructures is developed, recalling some properties as safety, security, emergency, vulnerability and stability. Then the implications of these considerations in control actions are briefly evaluated. The need to build a reference model useful to analyze and to simulate the phenomena connected with critical infrastructures is discussed. Investigating these concepts as the "emergence of properties" may be a chance; this point of view may be useful to identify and to evaluate a "systemic approach" to solve critical infrastructures problems. Some remarks about the complexity of the problems involved in managing the interaction between critical infrastructures are reported.