X-ray crystallography is often regarded as a science in its own right and indeed, there are many professional crystallographers who devote all their efforts to the development and practice of the subject. On the other hand, to many other scientists it is only a tool & as such, it is a meeting point of many disciplines - mathematics, physics, chemistry, biology, medicine & several others. However, for a crystallographer, the conventional boundaries between scientific subjects often seem rather nebulous as it has undergone an expansion of avalanche proportions in the last decade. Because of its wide applicability and its precision, it has become one of the most important tools in modern day research. The atomic structures, as revealed by X-ray crystallography are increasingly being used to provide detailed insights in to the functional behaviour and mechanism of a molecule. As a consequence, the belief is now widely held that external morphology is no longer of interest or importance and we are urged to adopt a ?new view-point? and to begin the study of crystallography in terms of the structural pattern of crystals.