INTRODUCTION Prologue Basic Principles of Protein Structure GEOMETRY Ellipsoids and Embedding Geometric Representations of Structure Distance Geometry Sticks to Strings Secondary Structure Geometries Simplified Architectures Sheets and Barrels Beta-Sheet Geometry Beta-Barrels CLASSIFICATION Networks and Domains Hydrogen-Bond Networks Protein Domain Definitions Protein Structure Comparison Overview of Comparison Methods Assessment of Significance Classification and Fold Spaces Protein Structure Classification Protein Fold Spaces A "Periodic Table" for Protein Structures Evolutionary' steps in fold-space TOPOLOGY Folds, Tangles and Knots Topology and Knots Random Walks in Fold-Space Protein Fold Complexity Structure Prediction and Modelling Random Folds from Distance Geometry Modelling with Distance Geometry Protein Tertiary Structure Prediction SYMMETRY Structural Symmetry Symmetry A Fourier Analysis of Symmetry Evolution and Origins Evolution of Structure and Function The Origins of Proteins The Secret of Life References Index.