Davies' Welding, now in its tenth edition, is an introduction to the theory and practice of welding processes and their applications.Part 1, explains the basic principles of physics, chemistry and metallurgy as applied to welding. The section on electrical principles includes a simple description of the silicon diode and resistor, teh production and use of square wave, and one-knob stepless control of welding current. There is a comprehensive section on non-destructive testing (NDT) and destructive testing of welds and crack tip opening displacement testing. Part 2, is a comprehensive survey of the welding methods in use today, and gives up-to-date information on all types of welding methods and tools.