This is an excellent introduction to the study of constitutions and the organization of government. The author did a wonderful job at selecting topics that related to each other and provided a rather complete bird's eye view of how economics can be used to study government. When I first browsed at its table of contents, I thought this was THE book I needed for my research on public administration and political economy(at least in this respect, the topics here are more cohesive than the smosgarbord of Persson and Tabellini's Political Economics or Drazen's Political Economy and Macroeconomics). Despite its breadth, however, Cooter's book lacks in depth of analysis, and this makes it more suitable as an undergraduate text or an introduction to nonspecialists. I agree with the first reviewer that the book is not very good at justifying assumptions and that the analysis provided can be simplistic at times. For instance, one major weakness stems from the author's obsessive adherence to the original methods of the field of Law and Economics; namely, the emphasis on basic price theory and microeconomic theory, which makes the book read more like an undergraduate text in (applied) economics. What is lacking, and this is what makes Persson and Tabellini's and Drazen's books superior, is a more systematic and rigorous use of contemporary tools such as game theory. Because it lacks rigor, this book is not suitable for research or reference purposes. It is also dated in the sense that it clings to a Law and Economics paradigm that is decades behind the latest work in positive or formal political theory.
If you are serious about studying economic models of politics for research purposes, I would suggest buying the following books:
1) Persson and Tabellini, Political Economics, MIT Press, 2000.
Written by economists, this book focuses TOO MUCH on economic policy, but the first part on foundations and analytical tools is one of the best I have seen. In their favor, the authors also do a good job at describing the frontier of research and the limitations of their book.
2) Drazen, Political Economy in Macroeconomics, Princeton 2000.
This book is also written by an economist, and, unsurprisingly, it is biased towards economic policy. Like the previous book, it has chapters that teach you the underlying models. In addition, the author does have a unifying theme throughout the whole book, so despite the various topics, you can make sense of the analytical power you gain by explicitly adding political elements to mainstream (macro)economic models.
3) For an overview of applications, you could either buy Cooter's book, or, in my view, a better book (in terms of depth, although less cohesive in substance) on public choice:
Dennis Mueller (ed.), Perspectives on Public Choice: A Handbook, Cambridge 1996.