Powder diffraction is the mostly widely used crystallographic method, with applications spanning all aspects of structural science. This new volume of International Tables for Crystallography covers all aspects of the technique with over 50 chapters written by experts in the field. Consisting of seven parts, this volume: Provides an overview of the principles of powder diffraction. Discusses the radiation sources used for powder-diffraction studies, instrumentation, the use of different sample environments and methods of sample preparation. Covers methodology, including data processing, indexing and reduction, whole-pattern modelling and quantitative analysis. An overview of the relevant crystallographic databases is also provided. Focuses on structure determination (including real- and reciprocal-space methods and the maximum-entropy method), structure refinement and structure validation. Discusses defects, texture and microstructure, including stress and strain, domain size and thin films. Reviews the available software for powder diffraction. Describes applications to many areas of industrial and academic importance, including macromolecules, minerals and mining, pharmaceuticals, ceramics, cement, superconductors, pigments, forensic science, archaeology, energy storage, petrochemicals and aluminium production. Volume H is the key reference for all powder diffractionists from beginners to advanced practitioners and has been designed to be a practical volume without sacrificing rigour. Many examples of the powder-diffraction method are discussed in detail, and in several cases the data used in the examples are available for the reader to download. More information on the series can be found at: https://it.iucr.org.