In the surge of interest in metre on the part of theorists in different disciplines and of practicing poets, the central issue has been that of variations in the iambic pentameter. David Keppel-Jones approaches this subject in a way that somewhat resembles Derek Attridge’s, but is in fact very different. Keppel-Jones’s study focuses on a period of 275 years, during which iambic pentameter variations were conducted with special precision. Representative blocks of verse are chosen from major poets in original authoritative editions, and each variation is analysed on the basis of all cases of that variation. To give precision to certain of the principles, Keppel-Jones follows the linguist Bruce Hayes’ definitions of boundaries between word-groups, but handles this material in such a way as to be understood by the general reader. Keppel-Jones found that the practical result of this study is a new metre that he could apply the principles of iambic variation to the anapest.