A growing number of governments are working to improve their performance by creating systems to measure and help them understand their performance. These systems for monitoring and evaluation (M&E) are used to measure the quantity, quality and targeting of the goods and services the outputs that the state provides and to measure the outcomes and impacts resulting from these outputs. These systems are also a vehicle to facilitate understanding of the causes of good and poor performance. The studies of this volume start by focusing on exactly what monitoring and evaluation has to offer to governments, then focuses on the experience of several countries that have succeeded in building a well functioning government. It analyzes the lessons from building government M&E systems in developing and developed countries, and at the end maps out those issues where international experience with government M&E systems is not well understood or well documented.