"The old order changeth, yielding place to new. " When Tennyson wrote this, he was unfamiliar with the pace of modem science else he would have said the new is displaced by the newer. When Gilbert and I gathered the papers for the first edition of this overview of metamorphosis, we aimed to provide a broad basis upon which the experimental analysis of the developmental changes called metamorphosis could proceed. We were both aware then that with the new techniques of biochemistry and with the revolutionary breakthrough to the nature of the gene, countless new possibilities were being opened...