The current book introduces the methodology of data envelopment analysis (DEA) as a data-oriented operations analytics. This data analysis tool analyzes multiple performance metrics, integrates multi-dimensional data into a composite index, and recommends directions for improvement. A number of DEA books have been written for conventional and new DEA models. Yet, many of these books still require fundamental and necessary knowledge on linear mathematical optimization. This book is uniquely designed to present the DEA methodology in an applied setting where a reader is not required to have the knowledge on linear programming and linear algebra.