Acta Crystallographica Section A

André Authier, Editor of Acta A.

Acta A is traditionally devoted to the "foundations of crystallography" and will remain so. Crystallography is to be understood in the broadest sense. As defined by H. Megaw, it is "the branch of science concerned with the description of the structure and properties of condensed matter in terms of the spatial relationships of atoms and interatomic forces in an extended array". This definition, written many years before the discovery of quasi-crystals, certainly includes extended arrays which do not necessarily have translational symmetry in three-dimensional space. In my understanding, crystallography also includes the study of defects or imperfections with respect to an ideal structure. Acta A will therefore continue to cover all experimental and theoretical studies of the properties of the arrangements of atoms, ions, and molecules in condensed matter, and the theoretical and experimental aspects of the various methods used for these studies. It should remain the high standard reference journal that it is in these domains.