Many materials are polycrystalline aggregates of tiny crystallites or grains of various sizes and shapes. Even for aggregates whose crystallites are chemically identical, the crystal lattices of the grains will still differ in their orientation in space. Since each crystallite is anisotropic in its physical properties, the macroscopic properties of a polycrystal will likewise be anisotropic unless the orientations of its constituent crystallites are completely random and the anisotropies of the crystallites even themselves out.

This fully revised and updated edition has been prepared by a very active worker in the field, who has used previous editions extensively both in teaching and in research, together with one of the original authors. Since the first edition, written in the late 1960s, understanding of crystal defects such as dislocations, stacking faults, twin, grain and interphase boundaries and of their effect on the mechanical and electrical properties of materials has grown enormously and has been accompanied by a total change in style of the way in which both research and teaching are carried out through the use of the fast digital computer. This edition takes account of this change. <...>

Some families of inorganic compounds form an array of more or less closely related, very complex structures with a number of independent atomic positions and unit cells of large dimensions. These structures can be broken up into a number of fragments (modules) that have relatively simple substructures but are joined into a more complex whole. Some modules occur in many members of these families, often in variably expanded/contracted forms as well as combined with elements of other kinds.

In this part, Chaps. 1 to 5, the crystal is studied as an ideal entity, from a geometrical point of view through the concept of lattice. The geometry and symmetry of the lattices and the external morphology of the crystals are considered. From a macroscopic point of view, the crystal is considered a homogeneous and continuous, anisotropic and symmetrical medium. When the internal symmetry is studied, the crystal is considered a homogeneous and discrete medium, as well as anisotropic and symmetrical.