This course covers an operational introduction to the dissipative quantum systems. Starting with a descriptive introduction we will introduce four essential techniques: I.Liouville Equation II.Generalized Master Equation III.Lindblad Equation and IV.Equations of motion approach, each of them will be illustrated with the help of following examples: driven quantum dot/ phonon which is an essential prototype for condensed matter systems and Jaynes Cummings model borrowed from quantum optics literature. Measurable observables relevant to experiments will be discussed. [more]