In the second lecture we shall look at more theoretical aspects of statistical mechanics. Beginning with the Lagrange and Hamiltonian description of classical mechanics we shall progress to the idea of phase space and the concept of a probability distribution function. This will be followed by basic applications (and associated mathematical manipulations) of the distribution function to obtain various physical properties of a system. We will examine the common ensembles (NVE, NVT and NPT) and discuss their application and interrelation. Finally we shall look at time dependence, beginning with the Liouville Equation and its connection with other time dependent equations. We shall conclude with the fluctuation-dissipation theorem.