Book excerpt: The Quarterly National Accounts Manual (the Manual) provides conceptual and practical guidance for compiling quarterly national accounts (QNA) statistics. The Manual offers a comprehensive review of data sources, statistical methods, and compilation techniques to derive official estimates of quarterly GDP. The new edition—which upgrades the first edition, published in 2001—improves and expands the previous content based on recent methodological advances, best country practices, and suggestions received from QNA compilers and experts.