In the last years there has been a great development of Genetics and Molecular Biology. These two disciplines have progressively exchanged conceptual categories and experimental methods, reaching an integration that represents the central and unifying theme of modern biology. This has created new areas of basic and applied research and expanded existing ones. This determined a strong demand for specialists in this field, able to conduct high-level research at universities, research centres and industry. Genetics, born as a science referred to the analysis of heredity, has quickly evolved to the study of structure and function of the hereditary material. This led genetics to become an essential component of almost every area of biology, as well as a discipline with a strong power in integrating different fields of biology. The results obtained in the first decades of this century have established that the genetic composition of an organism not only determines the various levels of phenotypic organization, but also how they interact with the environment in which it lives. Molecular biology in the last 40 years has made it possible to clarify the chemical/physical bases of many biological processes. The structure of the gene and its mode of replication, transcription and translation are now well known in their molecular details. More recently, "omics" methodologies have allowed studying the whole genome, transcriptome and proteome structure allowing the study of cell functions at a more global level. Moreover, the recent technologies of genetic engineering have provided a powerful means of investigation that made it possible to overcome those limits that were considered insurmountable until a few years ago by the very nature of biological systems studied.