Chapter 1 The Structure and Reactivity of Collagen 1.1 Occurrence and Industrial Significance of Collagen 1.2 What is Collagen 1.3 How is Collagen Formed 1.4 The Role of Water in Collagen 1.5 The Reactivity of Collagen 1.6 The Nature of Leather Formation and the Characteristics of Leather 1.7 Concluding Remarks Chapter 2 Physical and Chemical Processes on Collagen and Its Transformation into the Leather Matrix 2.1 Introduction 2.2 Preliminary Remarks 2.3 Principles of Tanning Theory, Basic Assumptions, Definitions and Methods 2.4 Diffusion and Penetration 2.5 Material Binding in and on the Collagen 2.6 Interaction Equivalents of Active Substances with Collagen 2.7 Summary Chapter 3 The Theory of Tanning--Past, Present, Future 3.1 Introduction 3.2 The History of Tanning Theory 3.3 Current Knowledge of the Nature of Tanning 3.4 Tanning Theory in the Future Chapter 4 The Significance of Water for the Structure and Properties of Collagen and Leather 4.1 Introduction 4.2 Collagen and Water: An Integral System 4.3 The Consequences for the Collagen Structure of a Change in Water Content 4.4 Water Determines the Collagen Characteristics 4.5 Thermal and Hydrothermal Stability of Collagen and Leather 4.6 The (Hydro) Thermal Stability of Collagen and Leather as a Function of the Water Content and Tanning 4.7 The Role of Water in the Conversion of Collagen to Leather 4.8 Tanning as Dehydration:A Chapter of Tanning Theory Chapter 5 Introduction of Modern Tanning Chemistry 5.1 Vegetable Tanning 5.2 Mineral Tanning 5.3 Oil Tanning 5.4 Aldehyde Tanning 5.5 Syntans 5.6 Combination Tanning Biography Appendix I Process Material Equipment Performance Appendix �� Prefix Suffix Appendix III Representative Research Articles