Chirality is defined formally as the property of objects that cannot be brought into congruence with their mirror image by translation or rotation. The word derives from the Greek X6ip that means hand and, in fact, the familiar name of “handed ness” may explain this property more readily. Like the hands, chiral objects are found in two forms that are mirror images of each other and are identical in their component parts but do not match when super-imposed because these parts have a different spatial distribu tion. Trying to put a right hand in a left hand glove or a left foot in a right foot shoe w ill give a convincing demonstration. Chirality is widespread in nature in a variety of two-and tri-dimensional forms (Fig. 7.1) and can also be associated with motion, for example, when an object describes a helix that can equally cross left to right or right to left such as in a screw.