Book excerpt: This book is dedicated to the branch of statistical science which pertains to the theory of hypothesis testing. This involves deciding on the plausibility of two or more hypothetical models based on some data. This work will be both interesting and useful for professional and beginner researchers and practitioners of many fields, who are interested in the theoretical and practical issues of the direction of mathematical statistics, namely, in statistical hypothesis testing. It will also be very useful for specialists of different fields for solving suitable problems at the appropriate level, as the book discusses in detail many important practical problems and provides detailed algorithms for their solutions.