This book presents selected proceedings of DEA45: International Conference on Data Envelopment Analysis, which was held September 4-6, 2023, at Surrey Business School, University of Surrey, Guildford, UK. It contains theoretical and empirical papers on Data Envelopment Analysis (DEA) and related fields with a focus on performance measurement and management. It discusses the latest research and developments and their application in various areas such as regulation, agriculture, education, financial and health services. The book is of interest to both researchers and practitioners working on or utilizing the DEA method for examining efficiencies across various organizations.