Diffuse neutron scattering from crystalline materials . By Victoria M. Nield and David A. Keen. Pp. xvi + 317. Oxford: Oxford University Press, 2000. Price GBP 69.50. ISBN 0-19-851790-4.

In this book, the authors have two stated aims. The first is: `to make diffuse scattering data interpretation more tractable'; the second is: `to provide an overview of the wide range of available interpretative methods, giving enough information for the reader to select the most useful tool for understanding his or her diffuse data, whilst avoiding elaborate and, to the non-specialist, possibly bemusing detail on any specific methodology'. I believe the authors have been admirably successful in meeting these aims. The book is an accessible and comprehensive guide to diffuse neutron scattering and, though written as an introduction to the technique for graduate scientists, will be a valuable reference text for any crystallographer keen to understand and apply modern interpretative techniques to diffuse scattering data. Though the emphasis of the book is undoubtedly on diffuse neutron scattering, with numerous practical examples taken from neutron studies, there is very little material that is not equally of interest to anyone working with X-rays or electrons. The extensive bibliog­raphies at the end of each chapter provide a comprehensive guide to the literature on all aspects of diffuse scattering.

The first chapter gives a brief historical review of the development of interest in diffuse scattering from its earliest beginnings, with the work of such famous names as Debye and Brillouin, to modern times, with current interest extending into protein crystallography. This chapter puts into perspective the special role of neutrons, as opposed to X-rays. The second chapter develops the theory of the basic scattering process specific to neutrons but, even here, X-ray workers will be able to benefit from seeing the differences and similarities in the comparable X-ray scattering theory. The third chapter deals with the theory of diffuse scattering and summarizes the different approaches that have been used to describe it. Important real-space concepts such as short-range-order parameters, size-effect and Huang scattering parameters are described, as well as alternative approaches founded in reciprocal-space descriptions. Again, in this chapter there is very little that is not equally applicable to X-ray scattering. Chapters 4 and 5 deal, respectively, with details of neutron-scattering data collection and data reduction. They provide a succinct description of the different kinds of instruments used and the information that can be obtained from them. Most importantly, reactor and spallation neutron sources are compared, with implications for the types of experiment that can be performed, providing a useful guide for the would-be experimenter. Chapter 6 details how analytical approaches to understanding and analysing diffuse scattering have been progressively replaced by various computer simulation and modelling techniques which allow more complex systems to be studied. Valuable introductions are given to molecular dynamics (MD), Monte Carlo (MC), reverse Monte Carlo (RMC) and the pair distribution function (PDF) methods. The remaining chapters describe, in varying degrees of detail, studies of systems of great diversity. Chapters 7 and 8 deal primarily with the more traditional subjects of substitutional disorder in alloys and simple oxides, and progress to more complex topics, including magnetic systems, quasicrystals and systems that include solvated hydrogen. The special ability of neutrons to see hydrogen and magnetic systems is emphasized. The final chapters concentrate on three specific areas prominent in recent years. Chapter 9 deals with superionic conductors including silver iodide and various fluorite-related phases, Chapter 10 considers molecular systems including ice, C₆₀, plastic phases, phases of various solidified gases, and Chapter 11 discusses framework structures, particularly in the context of the silica polymorphs.

My only slight criticism is that the book ends rather abruptly! Perhaps this is because the topic is one that is very much ongoing and the book relates only the `story so far'. A brief chapter devoted to possible future developments and directions would have nicely rounded off what is otherwise a really excellent volume.