This book proposes a summary of the various types of technological hazards, such as industrial, chemical, nuclear, exploitation, risks, and the transportation of dangerous matters (radioactive substances), and dams. some striking examples are given, like the AZF explosion in 2001 in Toulouse, as well as the nomenclature and legal evolution applied to these hazards. It also presents the main items of the European guideline sEVEsO II. (UNEsCO)