This book was first published in 1970. It addresses the increasing use of digital computers for equilibrium calculations in high temperature, high pressure processes, in rocketry and in explosives technology. It surveys the numerical techniques developed over the fifteen to twenty years preceding its publication. The authors derive the equations describing equilibria in different types of system and outline the effect of variation of the parameters of the system on the equilibrium composition. They discuss critically the available methods of solution of the chemical equilibrium problem, both in the minimization and non-linear equations form, and indicate the factors that should be taken into account in selecting the optimum method of solution for a particular problem and computer. The fundamental chemical and thermodynamic analytic material was selected so as to make the book fully accessible for students of chemical engineering, explosives and technology.