Unit 1 (items 1.1 and 1.2) includes an introduction to fundamental aspects of proteomics as a science. It describes the scope of this science and its origins and its main methodological strategies and applications. Moreover, it establishes the relationship between proteomics and other related sciences such as genomics, transcriptomics and metabolomics. Finally the concept of systems biology is defined as a global integration approach of the above terms. The events leading to such large-scale biology that integrates knowledge of the interaction between the components of living systems and of biological processes are shown.