This book has been written to assist the physicist and metallurgist by providing a reference work which contains information about the structures and lattice spacings of all binary and ternary alloys that have been examined. Part I of the work is intended as a general introduction 10 X-ray investigation of metals and alloys, and the author endeavours to show how structure determination and lattice spacing measurements can be important in giving information about the physical state of metals and alloys, particularly equilibrium diagram determination, and in corrcla-lion with electrical, maenctic and other physical properties. In Part II. which is a compilation and assessment of published X-ray work on metals and alloys in equilibrium, alloy systems are listed in alphabetical order according to accepted methods. An extensive and thorough surve> of the literature is given. The work ex-tends to over 1.000 pages, and includes numerous diagrams and main pages of tabulated data.