The atomic arrangements in condensed matter play an ever increasing role
in many areas of science and technology - Materials Science and
Engineering, Chemistry, Physics, Geology, Biology and Electrical, Civil,
Mechanidtl and Chemical Engineering. Exciting discoveries in these
fields in this century often stemmed from studies of these arrangements
using diffraction: the structure and functions of DNA and other
biological molecules, the configuration of polymer chains, the
crystalline nature of metals and their imperfections, semiconductors and
insulators, and -the links between their structures, their defects and
material properties, and the interaction between materials and the
environment. The broad, interdisciplinary character of diffraction
studies makes them particularly exciting. With new tools such as the
high-resolution electron microscope, new detectors, new techniques (such
as EXAFS and glancing angle diffraction) and the new sources, the
horizons of this field greatly expanded in the 1950's and 60's. Pulsed
neutron sources and high intensity storage rings that came on the scene
in the late 70's have opened up possibilities for new study to such vast
horizons that it is hard to sit here writing this - there's so much to
be done! Within the walls bounding each field of science or engineering,
diffraction and structure is only one specialty. It is too easy for this
topic to be developed in such a narrow way that sight is lost of the
basic principles and broad possibilities.