This is a great work in political philosophy and I certainly enjoyed reading it. It's very well written and it covers new ground in a penetrating and interesting manner. It offers far more food for thought than the average book in this field. The author's argument, as he summarizes it on p.38-39, is that "an epistemic approach to politics, morally constrained by a general acceptability requirement, generates a philosophically adequate basis for political authority".

First he discusses proceduralism - the thesis that democratic authority is justified by its fair procedures - and finds it insufficient by itself. Next he argues that democratic authority can also be epistemically justified due to its capacity to produce good decisions. Joining these two elements together, he defends his theory of "epistemic proceduralism" and discusses an analogy between democracy and juries at some length. All of the above basically constitutes the first half of the book, chapters 1-8.

The second half of the book, chapters 9-14, dives deeper into the problems of political knowledge. In these chapters the author explains why democratic arrangements produce "better decisions than random, and better than alternative arrangements, so far as can be determined within public reason" (p.160). He also discusses speech situations in democratic deliberation and rejects J.S. Mill's views on unequal voters and Condorcet's jury theorem of voting. All of these chapters are good, but they're a bit separate from each other and their contribution to the main argument in chapters 1-8 isn't all that big.

In the final chapter the author writes that "hopeless" normative political theory is needed even though its ideal theories have very little hope of being implemented in practice. Since this is another good chapter my criticism may be a bit misplaced, but I was bothered by this book's lack of realism on one particular point. Its arguments, especially those in the second half, are clearly geared towards direct democracy - situations where people decide directly by vote without intermediaries. Representative democracy is mentioned in passing on only three occasions (on pages 161, 182 and 260 by my count). The author hints that his arguments would apply to representation as well with a few caveats, but I wasn't exactly convinced. I would have liked to see at least one chapter on democratic representation in this book.

Maybe other works will eventually fill that gap. But in conclusion I think this is a path-breaking work. Epistemic theories of democracy have been around for a while, but there's still a lot of thinking to be done. This book sets a good standard and should inspire useful theorizing for a long time to come.