Crystallizing a Protein -- X-ray Sources and Detectors -- Crystals -- Theory of X-ray Diffraction by a Crystal -- Average Reflection Intensity and Distribution of Structure Factor Data -- Special Forms of the Structure Factor -- The Solution of the Phase Problem by the Isomorphous Replacement Method -- Phase Improvement -- Anomalous Scattering in the Determination of the Protein Phase Angles and the Absolute Configuration -- Molecular Replacement -- Direct Methods -- Laue Diffraction -- Refinement of the Model Structure -- The Combination of Phase Information -- Checking for Gross Errors and Estimating the Accuracy of the Structural Model -- Practical Protein Crystallization. X-ray crystallography has long been a vital method for studying the structure of proteins and other macromolecules. As the importance of proteins continues to grow, in fields from biochemistry and biophysics to pharmaceutical development and biotechnology, many researchers have found that a knowledge of X-ray diffraction is an indispensable tool. In this new edition of his essential work, Dr. Jan Drenth, recognized internationally for his numerous contributions to crystallographic research, has provided an up-to-date and technically rigorous introduction to the subject. Principles of Protein X-ray Crystallography provides the theoretical background necessary to understand how the structure of proteins is determined at atomic resolution. It is intended to serve as an introduction for graduate students, postdoctoral researchers, and established scientists who want to use protein crystallography in their own endeavors, or need to understand the subject in order to critically evaluate the literature. New additions to the book include a section on twinning, an additional chapter on crystal growth and a discussion of single-wavelength anomalous dispersion (SAD). Reviews: "The new edition... will bring important and significant, and timely, coverage of twinning and of SAD phasing." - Professor John Helliwell, Department of Chemistry, University of Manchester "a complete and up to date... single source of theory." - Duncan McRee, President, ActiveSight About the Authors: Dr. Jan Drenth is a professor emeritus at the Laboratory of Biophysical Chemistry at the University of Groningen, The Netherlands. Contributing author Dr. Jeroen R. Mesters Ph.D. is a Senior Research Assistant at the Institute of Biochemistry, University of Luebeck, Germany.