The construction principles of Celtic art were re-discovered in the middle of the 20th century by George Bain. Until his writing, the intricate knots, interlacings, and spirals used in illuminating The Book of Kells and in decorating craftwork and jewelry seemed almost impossible, "the work of angels." In this pioneering work, George Bain shows how simple principles, no more difficult than those used in needlecraft, were used to create some of...