This book presents the theory of soft matter to students at the advanced undergraduate or beginning graduate level. It provides a basic introduction to theoretical physics as applied to soft matter, explaining the concepts of symmetry, broken symmetry, and order parameters; phases and phase transitions; mean-field theory; and the mathematics of variational calculus and tensors. It is written in an informal, conversational style, which is accessible to students from a diverse range of backgrounds. The book begins with a simple "toy model" to demonstrate the physical significance of free energy. It then introduces two standard theories of phase transitions--the Ising model for ferromagnetism and van der Waals theory of gases and liquids--and uses them to illustrate principles of statistical mechanics. From those examples, it moves on to discuss order, disorder, and broken symmetry in many states of matter, and to explain the theoretical methods that are used to model the phenomena. It concludes with a chapter on liquid crystals, which brings together all of these physical and mathematical concepts. The book is accompanied by a set of "interactive figures," which can be downloaded from the publisher's website.

Some of these figures allow users to change parameters and see what happens to a graph, some allow users to rotate a plot or other graphics in 3D, and some do both. These interactive figures help students to develop their intuition for the physical meaning of equations. The book will be useful for advanced undergraduate or early graduate students going into theoretical research, to prepare them for more advanced studies--as well as for students going into experimental physics, chemistry, and engineering, who will be prepared to understand theoretical seminars, read theoretical articles, and collaborate with theorists.