This book is a comprehensive description of a software product called GENO that has been successfully tested on real-life and artificial problems, and against well-known methods embedded in popular scientific computing packages. GENO-an acronym for 'General Evolutionary Numerical Optimizer'-is a versatile solver that may be used on an exceptionally wide range of numerical problems: one may use it to solve simultaneous equation systems of all types, or to solve various classes of static or dynamic optimization problems. The method is relatively unfettered because it does not require the problem at hand to have a special mathematical structure; it may also be set to generate real or integer-valued solutions, or a mixture of the two as required. The book begins with a generic statement of the mathematical model that underlies GENO's design together with brief statements on how to specialize the model (by mere choice of a few program parameters) so as to address specific problem types; it include a set of fully-worked examples that span the 'applicability spectrum' of GENO; and it ends with a set of appendices comprising: (i) an essay on the main numerical method employed by GENO-namely evolutionary search; (ii) a classification and index of the example programs that ship with the product; (iii) an 'applicability map' that vividly illustrates the relative advantage of GENO when compared to twenty other numerical solution methods that are currently available.