The last decade or so has seen a dramatic increase in the amount of detailed structural information available from a range of experimental techniques. Exciting new techniques such as atomic force microscopy have become widely available, while the potential of established methods like X-ray diffraction and electron microscopy has been greatly enhanced by powerful new sources and analytical methods. Progress in computing has also had a widespread impact: in areas such as neutron scattering, large data sets can now be manipulated more readily. The software supplied with commercial instruments...