There is a growing interest in developing register-based surveys; that is surveys based upon already available administrative data. Since huge amounts of such data are generated within various administrative systems, the opportunity exists to use the data for statistical analysis without any of the costs involved in data collection. Register-based surveys require their own methodology and the development of these methods is an important challenge to statistical science. Instead of methods on how to collect data, methods for integrating data from different sources are necessary. How should administrative data be transformed to meet the statistical needs? Register-based Statistics offers readers a detailed account of the principles and practices of this increasingly popular area of statistics. Provides a comprehensive overview of register-based statistics, both in terms of theory and advanced application. Uses real life examples taken from Statistics Sweden to illustrate fundamental global principles. Proposes a much-needed systematic terminology for the field. Describes how to create statistical registers and a methodology for integration of data from many sources as a key tool for the future. Develops estimation methods and quality concepts for register-based surveys. Discusses statistical systems consisting of many statistical registers and surveys, highlighting the importance of consistency and coherence. Register-based Statistics provides a unique guide for all those working in statistical agencies. It will also prove invaluable for academic researchers and teachers in statistics, and statisticians working with administrative systems in government institutions and enterprises.