This course first introduces the principles and methods of Classical Thermodynamics and the thermodynamic laws (first and second) in relation to familiar experience of equilibrium, work, heat, and amount of matter. The course shows how Equations of State calibrated on equilibrium data can lead to the identification of Thermodynamic Functions (Internal Energy, Enthalpy, Entropy, Gibbs Energy, Helmholtz Energy and Chemical Potential) and how these can be can be practically retrieved by using also other measurable thermodynamic quantities (specific heat capacity, expansivity and isothermal compressibility). This is delivered in the context of pure fluids and used to describe the performance of single reversible transformations, power generation and refrigeration cycles.