The introduction to the book "Introduction to Data Envelopment Analysis and Its Uses" provides a comprehensive overview of the field of Data Envelopment Analysis (DEA). The authors, William W. Cooper, Lawrence M. Seiford, and Kaoru Tone, highlight the importance of DEA in evaluating the performance of various entities, including business firms, government agencies, and non-profit organizations. DEA is described as a method that "envelops" observations to identify an efficiency frontier, which is used to assess the performance of entities. The book covers different types of efficiency, such as allocative, price, scale, technical, and mix efficiency, and explains how DEA identifies sources and amounts of inefficiency. The authors also discuss the engineering-science definitions of efficiency and their relationship to the Pareto-Koopmans definition, which is more general and applicable in welfare economics. They emphasize the use of linear programming and duality to simplify DEA models and make them more accessible. The book includes numerous examples and numerical illustrations to help readers understand the concepts and methods. Additionally, the book addresses extensions and further uses of DEA, such as handling non-discretionary and categorical variables, and provides a detailed strategy for presenting the material to both practitioners and students. The authors aim to make the book self-contained and provide references for further exploration. The first five chapters are designed to serve as an introduction to DEA, covering various models and their applications, while subsequent chapters delve into more advanced topics.The introduction to the book "Introduction to Data Envelopment Analysis and Its Uses" provides a comprehensive overview of the field of Data Envelopment Analysis (DEA). The authors, William W. Cooper, Lawrence M. Seiford, and Kaoru Tone, highlight the importance of DEA in evaluating the performance of various entities, including business firms, government agencies, and non-profit organizations. DEA is described as a method that "envelops" observations to identify an efficiency frontier, which is used to assess the performance of entities. The book covers different types of efficiency, such as allocative, price, scale, technical, and mix efficiency, and explains how DEA identifies sources and amounts of inefficiency. The authors also discuss the engineering-science definitions of efficiency and their relationship to the Pareto-Koopmans definition, which is more general and applicable in welfare economics. They emphasize the use of linear programming and duality to simplify DEA models and make them more accessible. The book includes numerous examples and numerical illustrations to help readers understand the concepts and methods. Additionally, the book addresses extensions and further uses of DEA, such as handling non-discretionary and categorical variables, and provides a detailed strategy for presenting the material to both practitioners and students. The authors aim to make the book self-contained and provide references for further exploration. The first five chapters are designed to serve as an introduction to DEA, covering various models and their applications, while subsequent chapters delve into more advanced topics.