The equation of state (EOS) is the relation between the pressure, temperature and the volume of a physical system and is related both to fundamental physics and to application in astrophysics, condensed matter, gases, nuclear and elementary particle theory. Hence, the aim of the book is to develop an equation of state (EOS) of condensed matter and apply it to obtain the various physical properties like acoustic properties of liquids (e.g., sound speed and non-linear parameter), thermodynamic properties (e.g. Gibb's energy, entropy, heat capacity etc.) and activated properties (e.g. self-diffusion coefficient, activation volume, activation energy, and activation entropy and activation heat capacity). Much of the material on which this book is based, is published under different publishers. I would like to specially acknowledge to Dr Narsingh Dass for his very ironic contribution to the work presented in this book.