'I was searching for a better description of liquids when I encountered Professor Trachenko's work, and immediately recognized its elegance and power. I truly enjoyed reading his book: his lucid explanations and critical insights on Frenkel's work and his objective assessment of the deficiencies of other approaches. This book not only revitalizes Frenkel's theory but elevates it to new heights. Professor Trachenko's book lays the foundations for more advances to come.' Gang Chen, Massachusetts Institute of Technology 'Over the past decade there have been enormous advances in our understanding of liquids and supercritical fluids due to new theoretical proposals, the rediscovery of old theoretical proposals, and new experimental findings. This text provides a single comprehensive and cohesive account of these developments, placing them in the context of our mature understanding of the solid and gas states. There is a focus throughout on how we can understand the properties of real liquids - viscosity, heat capacity etc. - that determine their behaviour in everyday life and in planetary interiors. Reading it has made me appreciate just how urgently such a text was required. It will certainly become a key text in my collection and, I am sure, in the collection of other scientists with an interest in the nature of the basic states of matter.' John Proctor, University of Salford 'This book provides an excellent introduction to the theoretical aspects of physical liquids in the 21st century, written by the foremost expert on the subject I highly recommend this text to any condensed matter theorist (graduate level and above), who has some interest in the theoretical aspects of liquids.' Kymani Tieral Keden Armstrong-Williams, https://physicsbookreviewer.blogspot.com/ ' an excellent resource for anyone interested in working in this area. Recommended.' D. B. Mason, Choice