This book explores the monitoring, reporting, and verification (MRV) of greenhouse gas emissions as practiced within the climate economy—particularly in operational carbon pricing mechanisms and emission quantification for management purposes. It provides an overview of MRV procedures in fifteen major policy frameworks, including national greenhouse gas inventories under UN oversight, the EU Emissions Trading System, the Australian carbon tax, and the UN-supervised Clean Development Mechanism. These frameworks are compared based on key criteria such as scope, cost, uncertainty, and flexibility. The book emphasizes practical challenges and real-world solutions used in existing MRV systems, rather than theoretical or science-driven approaches. It does not cover MRV of climate finance or policy effectiveness, nor does it delve into future, undefined frameworks like Nationally Appropriate Mitigation Actions (NAMAs). Aimed at a general audience, the book is written by engineers and economists actively working in the field, offering insight into the practical stakes and choices involved in emission MRV.