This textbook provides a thorough and systematic understanding of carbon fractions and the laboratory procedures for their estimation. It serves as both a practical lab manual and an educational guide, fostering knowledge dissemination and skill development in soil carbon research. It consolidates all procedures related to soil carbon fractionation, including active-, slow-, and passive-carbon pools into one document, with detailed methodologies. For complete and proper implementation, each method is provided with relevant chemical reactions, principles, and a step-by-step protocol in the form of flowcharts and calculations. This book is designed for streamlining the workflow for soil researchers and reducing preparation time. It promotes high-end carbon analyzers for sustainable, low-waste alternatives to traditional methods, aligning with modern environmental and agricultural resilience goals. This book is exclusively for advanced graduate students and researchers working in the field of soil science and related disciplines.