Solitons play a fundamental role in ordering processes in crystals, where the collective motion is essential for mesoscopic disorder in thermal equilibrium. The first edition of this book detailed the essential mechanism of structural changes where solitons play the fundamental role of boson statistics for irreversible thermodynamics in crystals; explaining the structural transformations and mesoscopic disorder, and the nonlinear mechanism of superconductivity. A major development and extension presented in this new edition is in the application of soliton theory to polymers and liquid crystals, in addition to capturing the theoretical developments and newer experimental results of soliton analysis in general. This updated text also emphasises the thermodynamics of soft modes, pseudospins and order variables for finite lattice displacements. Soliton statistics of the nonlinear order variables are also logically discussed. Written as an introductory treatise, with respect to the soliton concept in matter, with exercises provided, this book will help to further develop readers' understanding of the subject.