Quantum mechanics is one of the most predictive and widespread physical theories we know. It allows us to describe the atoms and constituents of matter, but it also allows to understand the assemblies of molecules, the nature of light and the structure of solids. Quantum mechanics, as a fundamental science, is also at the origin of great applications upon which are based our modern society: most high-tech products are directly derived from quantum concepts (computer, laser, GPS, MRI ...). The objective of this course is to offer an introduction to quantum mechanics and its general principles using the Dirac formalism.