This book is primarily for optimization courses at universities, engineering schools and business schools but it can be used by engineers, economists and others who work with optimization applications and optimization theory also. Lundgren, Ronnqvist and Varbrand describe how optimization models can be formulated and include basic optimization theory, solution methods, practical use of the solver in Excel and the modeling language AMPL. Topics include linear programming, network optimization, nonlinear optimization, integer programming and dynamic programming. Models and methods are illustrated with a large number of examples and figures. This is the English edition of the Swedish book Optimeringslära (2008). The two editions are virtually equivalent and can be used for teaching in both English and Swedish. There is also a supplementary exercise book (versions in both English and Swedish) with a large number of exercises and solutions.