Professor Beatty's book, The Ultimate Rule of Law is a timely contribution to a number of important and intersecting debates in constitutional theory, jurisprudence and European law. The principal issue this book addresses is the increased importance of constitutional law and adjudication at national, supranational and even transnational levels. In a number of jurisdictions, it is now commonplace that matters of political importance and controversy are subject to constitutional adjudicative decision-making. At the same time, we have also seen something of a renaissance of general constitutional theory, albeit a constitutional theory that is critical or at least wary of these trends. Hegelian-Marxist, Communitarian and Schmittian critiques of liberal constitutionalism have been revived in order to articulate a range of concerns over the limits and sustainability of these same trends.1 Even from within self-consciously liberal perspectives, the attractions of the institution of constitutional review as a constraint on the ordinary political process will have diminished for those convinced by Waldron's ‘rights-based’ argument in favour of the primacy of ordinary legislative procedure.2 It should also be noted that more sanguine assessments of the strengths of constitutionalism have been offered, most notably by Jurgen Habermas.3 As can be seen from this cursory survey, the range of scholarship inspired by the phenomenon of constitutional review is extremely broad. Scholarship in the areas mentioned earlier articulates a wide variety of intuitions, employs a number of different methodologies and addresses distinct sets of problems. Given this diversity, any attempt to provide a unified account of this field is likely to encounter a number of difficulties. Beatty's work is at once modest and ambitious in this respect. The book in essence makes a strong case in favour of basing constitutional adjudication on one overriding principle, the principle of proportionality. The argument is supported by a first, theoretically orientated chapter in which Beatty explores the limits of the debate concerning the difficulties of reconciling entrenched judicial review with a commitment to democracy. The second supporting pillar of his argument comprises a comparative analysis of constitutional cases arranged in accordance with three general headings: liberty, equality and fraternity. Beatty's argument, though admittedly relatively ambitious in scope, therefore, does not directly address certain of the debates and issues mentioned earlier. For scholars working in these different fields, however, Beatty's book will provide a variety of practical and theoretical insights into their particular area of study. His assured, direct and elegant approach to the debates on the legitimacy of judicial review provides a refreshing and thought-provoking overview of the essentials. His more detailed commentary on the comparative constitutional material will provide readers of the book with some interesting practical applications of constitutional provisions to consider. The first part of this article will examine Beatty's argument that constitutional theory in the US context has come to something of a dead end and the lessons to be drawn from this. The second part examines the substance of Beatty's argument in this book; namely, the view that constitutional review ought to be guided by the principle of proportionality.