After a brief survey of the basic definitions, the various modes of ionization (EI, CI, FAB, ESI, APCI, APPI, MALDI, DESI, DART) will be described in details. The different analyzers (Quad, triple Quad, Ion trap, TOF, Orbitrap, FTICR) will be presented together with their possible scanning modes and their combinations. Couplings with GC and HPLC will be presented. The interpretation of spectral data will first emphasize the differences between low resolution and low accuracy versus high resolution and high accuracy data. The importance of the isotopic cluster will be demonstrated. The principal rules of fragmentation of radical-cations will be presented together with some basic rules for the fragmentation of ions with even-number of electrons. Selected examples and exercises will be explicitly studied in this part of the course. At the end of the course, a short introduction to the use of mass spectrometry in diverse fields (analysis of non-covalent species, of proteins, inorganic compounds,…) will be given.