[1.] Introduction; [2.] The structure of skin; [3.] The preparation of parchment; [4.] Disease and environment; [5.] Examination of parchment [examines flaws in five RIA MSS: Cathach of St. Columba, Lebor na hUidre, Leabhar Breac, Book of Lecan and Book of Fermoy]; [6.] Age and size of animals; [7.] Herd management; [8.] Cost of production; [9.] Position and size of flaws; [10.] Discussion.