11 November 2012 marks the centenary of the reading of the paper by William Lawrence Bragg (WLB) to the Cambridge Philosophical Society outlining the foundations of X-ray crystallography. It included the derivation of the first correct atomic structure of a crystal, namely that of zinc blende, based on the X-ray diffraction pattern recorded by Friedrich, Knipping and Laue in the spring of 1912. At the time of the lecture, Lawrence Bragg (as he later preferred to be called) was 22 years old and still a research student in the Cavendish Laboratory.

This special issue of Acta Crystallographica Section A is dedicated to commemorating this landmark scientific event, the ramifications of which have served as a wellspring for many other branches of science, including structural chemistry, mineralogy, materials science, solid-state physics and molecular biology.