This magisterial study joins the ranks of other epic examinations of British and European aristocracy, such as those undertaken by Lawrence Stone, Keith Brown and Hamish Scott. Indeed Jane Ohlmeyer employs many of their works to assist her in this extensive exposition, with which she successfully fills the long extant void of a dedicated survey of the Irish nobility in the seventeenth century. Ohlmeyer divides her work into three broad areas of focus. The first considers the political, cultural and religious reconstitution of the Irish peerage in the century after 1590, and the concomitant emergence of a ‘protestant service nobility’. The second provides a chronological assessment of the role played by the Irish peers in politics, parliament and at court. Their varied experiences during and following the Wars of the Three Kingdoms is also addressed here in detail. The final section discusses the ‘vertical bonds that sustained the peerage’, which includes some illuminating chapters on the evolving sources of income, levels of expenditure and debt, and the significance of death as an opportunity to propagate dynastic achievement. Ohlmeyer's primary task is to portray the dramatic cultural transformation of the peerage during the period; how a mostly Catholic Gaelic Irish and Old English nobility was replaced by a primarily parvenu Protestant New English and Scottish aristocratic elite, which would go on to form the ruling Ascendancy class of the eighteenth century. This transformation was achieved via the fluid nature of landownership, so fundamental to the status of the peerage, and is meticulously detailed in a revealing cadastral chapter. It is the complex character of the ninety-one resident noble families that clearly fascinates the author, where the lines between native and newcomer, Protestant and Catholic were continuously blurred through political and economic interdependence, marriage and by religious conversion. Indeed the weighty issues dealt with throughout this work are rendered accessible to the reader by the proliferation of case studies and anecdotes, reminding us that the subject of the book is as much concerned with individuals as it is with their social class. It is unfortunate however, that the quality of the tables and appendices that so clearly illustrate the author's thesis, was not equalled by that of the numerous maps, which are difficult to use, and in places impossible to interpret. The extensive series of endnotes clearly demonstrates that Ohlmeyer's opus is based on a career's worth of archival research, which has been complimented by reliably familiar secondary sources. One wonders however, how much her conclusions would have been confirmed or challenged, had she incorporated more recent doctoral studies completed in institutions on both sides of the Irish Sea on various aspects of the Irish aristocracy and the wider noble class. However, neither of these issues, nor the few biographical errors throughout, can detract from the fact that this worthy tome will be an essential text for any historian of seventeenth-century Ireland for some time to come.