Every trade is also a tribe, booksellers no exception, and one way that a mercantile tribe signals membership is by language and price symbols, that is to say the cost or price code. Here are codes aplenty, 226 plus another eighteen in a sheet of Addenda, the total twice as many as the number in Ian Jackson's earlier edition of 2010. The codes, ancient and modern, are presented with accompanying commentary in an attempt to combat the bibliographical neglect of their study. Roger Stoddard in his Marks in Books (Cambridge, Mass., 1985) ignores them; David Pearson's Provenance Research in Book History (London, 1994) does not venture beyond the seventeenth century. The orthodox cost code, scribbled on an endpaper, is a substitution code consisting of a series of non-repeating letters corresponding to certain numbers, usually either 1–9, or 1–10 if incorporating a zero. The bookseller will choose or coin an accommodating word or phrase according to taste (or lack of); sometimes the name of the bookseller in question, say ROSENTHAL; maybe a place, TUXEDO PARK; or the impossible dream, INTROUVABLE. Others may reflect a business attitude, from MY GOD HELPS to MONEY TALKS, even BANKRUPTCY.