I Experimental Data on Mechanical Twinning.- 1. Twinning with Change of Form.- § 1. Geometry, Crystallography, and Relation to Atomic Structure.- 1. Idealized Schemes for Translational Slip and for Twinning with Change of Form.- 2. Twinning Equivalent to Homogeneous Deformation: Twinning Ellipsoid and Elements of Twinning.- 3. Conjugate Twins and Twins of the First and Second Kinds.- 4. The Main Geometrical Laws of Mechanical Twinning.- 5. Some Additional Aspects of Twin Geometry.- 6. Analytic Condition for a Crystal Lattice to Twin by Simple Shear.- 7. Transformation of Indices of Planes and Directions in Twinning.- 8. Deviation of Twinning from Deformation by Simple Shear.- 9. Redistribution of Basic Particles in Twinning with Change in Form.- 10. Laves's Rule for Projecting the Twin Plane on the Shear Plane:Limit of Possible Deviation from Deformation by Simple Shear.- 11. Change of Length in Mechanical Twinning.- 12. Experimental Determination of Elements of Twinning.- 13. Elements and Laws of Twinning for Crystals of High Symmetry.- 14. Twinning in Crystals of Low Symmetry.- 15. Disposition of Atoms in the Twin Boundary When This is Parallel to the Twin Plane.- 16. Structure of a Twin Boundary Deviating from a Twin Plane: Formation of Accommodation Bands and Shape of Twin Layers.- 17. Geometry of Intersection of Twin Layers.- 18. Prediction of Twin Elements for Metal Crystals.- 19. Examples of Prediction of Twin Elements.- § 2. Production and Evolution of Twins in Response to Mechanical Stress.- 1. Methods of Producing and Detecting Mechanical Twins.- 2. Formation of Mechanical Twins in Calcite: Polysynthetic Twins, Detwinning, Parting Planes, and Channels.- 3. Elastic Twinning and Wedge-Type Elastic Twins.- 4. Surface Relief of Calcite in Elastic Twinning.- 5. Role of Localized Loads.- 6. Stages of Twinning: Elastic Limits and Yield Point.- 7. The Law of Critical Shear Stresses.- 8. Work of Formation for an Elastic-Twin Layer: Invariant of Deformation in Twinning.- 9. Rate of a Twinning Process: Jumps in Twinning, Deformation Curves, and Jumps in Deformation.- 10. Work-Hardening as a Result of Mechanical Twinning.- 11. Displacement of a Twin Boundary Under Stress.- 12. Twinning and Slip Along a Common Crystallographic Plane.- 13. Effects of Dimensions on Resistance to Twinning: Twinning in Crystals with Few Dislocations.- 13a. Effects of Real (Mosaic) Structure on Twinning; Effects of Impurities.- 14. Interaction of Intersecting Twin Layers.- 15. Effects of Temperature, Hydrostatic Pressure, and Deformation Rate on Elastic and Inelastic Twinning.- 16. Hardening of Calcite During Annealing; Elimination of Twin Layers by Annealing and Recrystallization of Layers.- 17. Cracking Along Twin Boundaries, Secondary Cleavage, Fatigue Cracks, Cold-Shortness in Metals; Twinning and Deformation Textures.- 18. Change in Internal Friction on Twinning in a Simple Crystal.- 19. Twinning in Rochelle Salt.- 20. Twin Components as Regions of Spontaneous Polarization.- 21. Elasticity of an Alloy: Analogy with the Elasticity of Rubber.- 22. Distribution of Residual Stresses in Displacement for the Boundaries of Polysynthetic Twins and of Domains.- 2. Twinning Without Change of Form.- § 3. Geometry, Crystallography, and Relation to Atomic Structure.- 1. Laws of Twinning for Natural Quartz Crystals.- 2. Residual Mechanical Twins in Quartz Produced by Localized Loading; Methods of Detecting Twins, Shapes of Twins, and Twin Axes.- 3. Redistribution in the Formation of Dauphiné Twins; Ideal Spatial Form of a Mechanical Twin and Atomic Structure of Twin Sutures.- § 4. Production and Development of Twins.- 1. Strength of Quartz: Role of Localized Stresses, Anisotropy of Twinning Forces; Flow at Room Temperature, Roles of Temperature and Time.- 2. Twinning of Quartz Plates Under Stress; Monocrystals Produced by Torsion and Vector Model of Twinning.- 3. Stages of Twinning in Quartz; Sense of Displacement of Twin Boundaries and Relation to Sign of Stress.- 4. Patterns of Twin Boundaries and the Stored Elastic Energy.- 5. Differences and Similarities in the Mechanical Twinning of Quartz and Calcite.- 6. Morphology of Twinning in Quartz.- 7. Practical Significance of Monocrystallization; Methods of Detwinning Quartz and Effects of Various Factors.- 8. Twinning in Triglycine Sulfate.- 9. Electrical Displacement of Twin Boundaries in Triglycine Sulfate.- 3. Twinning During Plastic Deformation and Fracture of Polycrystals.- § 5. Twinning in Polycrystals: Effects of Grain Size.- § 6. Twinning and Fracture of Polycrystals.- II Effects Related to Mechanical Twinning.- 4. Martensite Phase Transitions.- § 7. Cooperative and Other Phase Transitions.- § 8. Macroscopic Shear in Cooperative Transitions: Classification of Cooperative Transitions.- § 9. Main Features of Martensite Transitions.- § 10. Elastic Crystals of Martensite: Effects of Deformation on Martensite Transitions.- 5. Recrystallization Twins.- § 11. Processes in Deformed Crystals at High Temperatures.- § 12. Nucleation of Recrystallization Centers.- §13. Development of Annealing (Recrystallization) Twins.- 6. Lattice Reorientation in Inhomogeneous Deformation.- §14. Geometry, Crystallography, and Relation to Atomic Structure.- 1. Irregular Lattice Reorientation by Mechanical Stress.- 2. Historical.- 3. Types of Reorientation: Irrational Twins, Kink Bands, Plates, Deformation Bands, Accommodation Bands, and Brilliantov-Obreimov Bands (Irrational Twins).- 4. Relation of Mechanical lattice Reorientation to Slip and Twinning.- 5. Optical and X -Ray Evidence on the Structure of Kink Bands.- 6. Effects of Orientation on the Production of Mechanically Reoriented Regions.- §15. Production and Development of Reoriented Regions.- 1. Stress Distributions Producing Irrational Twins and Kink Bands.- 2. Rate of Kink-Band Formation, Displacement of Kink Boundaries by Mechanical Stresses, and Effects of Impurities.- 3. Effects of Temperature and Deformation Rate on the Formation of Kink Bands and Brilliantov-Obreimov Bands.- 4. Shape of Stress-Strain Curves in Kink-Band Formation; Test of Law of Critical Shear Stress.- 5. Kink Bands and Irrational Twins in the Plastic Deformation of Monocrystals.- 6. Kinking and Fracture.- §16. Formation of Kinks and Disoriented Microregions in Polycrystalline Metals.- III Theory of Twinning.- 7. Macroscopic Theory of Twinning.- §17. A Thin Twin as a Fracture Surface.- §18. Twin Boundary on a Fracture Surface.- §19. Energy of Twinning With and Without Change of Form.- 8, Microscopic Theory of Twinning.- §20. Transition Zones on Twin Boundaries.- §21. Sharp Twin Boundaries: Atomic Steps on a Twin Boundary.- §22. Twinning Dislocations and Stresses.- §23. Stacking Faults as Monolayer Twins.- §24. Atomic Model of Twinning..- §25. Difficulties; Problems of Nucleation.- Appendix 1: Selective Etching as a Means of Studying Twinning.- Appendix 2: Selective Etching Applied to the Dislocation Mechanism of Twinning With Change of Form.- Appendix 3: Selective Etching Applied to Twinning Without Change of Form.- Literature Cited.- Author Index.