I. Characteristics of environmental problems and protection models of the environment founded on the private law: I. The twelve features of environmental problems. II. Protection models. The management of environmental problems entrusted to private law. II. Environment protection models entrusted to the State intervention: I. Command and control. II. Market Tools. III. Legal qualification of environment: I. Significance of the matter and analysis of the main theses. II. The environment as a duty. III. Some corollaries of the theory. IV. The principles: I. The responsibility as expressed by principles. II. Sustainable development. V. The environment in the Constitution, in the European Law and in the International Law Framework: I. A look at the Italian legal system: Environment, Constitution and legislative competence. II. Environment in the European Union. III. The Environment in the EHCR (European Convention on Human Rights) and in the International Law.