The Legal Theory Bookworm recommends Unconstitutional Constitutional Amendments: The Limits of Amendment Powers by Yaniv Roznai. Here is a description:
Can constitutional amendments be unconstitutional? The problem of 'unconstitutional constitutional amendments' has become one of the most widely debated issues in comparative constitutional theory, constitutional design, and constitutional adjudication. This book describes and analyses the increasing tendency in global constitutionalism substantively to limit formal changes to constitutions. The challenges of constitutional unamendability to constitutional theory become even more complex when constitutional courts enforce such limitations through substantive judicial review of amendments, often resulting in the declaration that these constitutional amendments are 'unconstitutional'.
Combining historical comparisons, constitutional theory, and a wide comparative study, Yaniv Roznai sets out to explain what the nature of amendment power is, what its limitations are, and what the role of constitutional courts is and should be when enforcing limitations on constitutional amendments.
And from the reviews:
"An unconstitutional constitutional amendment-does it exist? More often than you may have thought. But rarely has it been explored. This book, which truly fills a gap, gives a thorough account of and a theoretical foundation for constitutional unamendability-a subject that gains more and more importance in modern constitutionalism." – Dieter Grimm, Professor of Law at Humboldt University Berlin, Visiting Professor at Yale Law School, and Justice of the Federal Constitutional Court of Germany (1987-1999)
"The theory of constitutional amendments has, somewhat surprisingly, emerged as one of the most central questions for contemporary constitutional theory. Providing a comprehensive overview of worldwide practice regarding judicial review of constitutional amendments, Yaniv Roznai offers the most sophisticated theoretical account yet of constitutional amendments. This is a work of fundamental importance to everyone concerned with the basics of constitutional theory." – Mark Tushnet, William Nelson Cromwell Professor of Law, Harvard Law School
"This excellent book is not just another addendum to the list of technical problems handled by constitutional experts. In his analysis of the character of the amending power – 'an exceptional authority, yet a limited one' – Yaniv Roznai reaches the very core of constitutionalism. Setting aside the formal positivistic framework, his rich and illuminating reconstruction of the role of 'the people' and the meaning of democracy in a constitutional polity refreshes and deepens the understanding of liberal democracy. In times when liberal democracy is under severe stress almost everywhere and challenged by advocates of illiberal democracy, this book could not be more timely." — Ulrich K. Preuß, Professor Emeritus, Freie Universität Berlin and Hertie School of Governance, Berlin
"Roznai's book provides a comprehensive and detailed analysis of unconstitutional constitutional amendments. Roznai discusses the constitutions containing provisions regarding this fascinating phenomenon (be they express or implied), and the courts' reactions to them. The book provides an in-depth analytical review of the problems that eternity clauses present the political authorities and the courts. This is an excellent book that discusses one of the central problems of modern constitutionalism." – Aharon Barak, Professor of Law, Radzyner Law School, The Interdisciplinary Center Herzliya; Visiting Professor of Law and the Gruber Global Constitutionalism Fellow at Yale Law School; Former President of the Supreme Court of Israel
"The book skilfully introduces the phenomenon of unconstitutional constitutional amendments and provides a sophisticated justification for constitutional unamendability… The book's appeal is not only to those studying constitutional change, but also to scholars of comparative law and comparative politics, as well as those brooding over what it means to uphold democracy. It also promises to be an invaluable reference book with its extensive bibliography… Institutional and personal libraries alike had better make room for Unconstitutional Constitutional Amendments." – Tarik Olcay, Constitutional Change