This book contains the following contents: Part 1. Commentary ------------------------------ The Basis of Age-Hardening Changes in Mechanical and Physical Properties on Ageing X-ray and Electron Metallography of Ageing The Metallography of Deformed Alloys, and Theories of the Mechanisms of Hardening Part 2. Papers --------------------- The Slip Interference Theory of the Hardening of Metals by Z. Jeffries and R. S. Archer Physical-Metallurgical Experiments on Aluminium Alloys Containing Magnesium by A. Wilm Precipitation Hardening of Aluminium-Magnesium-Zinc Alloys and Reversion through Age Hardening by W. Koster and K. Kam The Plastic Deformation of Age-Hardened Aluminium Alloys by R. J. Price and A. Kelly Kinetics of Clustering in Some Aluminium Alloys by D. Turnbull, H. S. Rosenbaum and H. N. Treaftis The Diffraction of X-Rays by Age-Hardening Aluminium Copper Alloys by G. P. Preston Structural Ageing Characteristics of Binary Aluminium-Copper Alloys by J. M. Silcock, T. J. Heal