The Celtic scribes of the sixth to ninth centuries, whose intelligence and artistry we admire today in their sacred manuscripts, worked from instructions and master-copies, handed down from generation to generation. In this authoritative reference manual, the sources and symbolism of their ornament are made accessible. From elucidation of the pages of the Cathach of St. Columba to the Celtic animal alphabet, this unique blend of history, anecdote and practical instruction recreates the schooling of the Celtic illuminator.