In short, this book is significant but poorly argued and structured. It operates largely on the assumption that certain models of transaction will strike us as "intuitively" unethical. Which is to say, he side-steps the toughest job in ethics, which is to genuinely persuade a person to make a certain decision and just assumes we already will. In other words, he offers almost no argument at all.
The book is also poorly structured and reads more like a collection of essays and short stories than a thesis. It makes the point muddled and definitions get mixed up and vague. Add to this the increasing obscurity of his prose (guided by his formal logic background) and the book becomes almost unreadable.
The book is worth reading if you have an interest in the history of modern political writing. It is structured largely as a response to the far superior "Theory of Justice" by Rawls. It's important for a few reasons, then. First, it is something that has captured a section of the population's attention as of late. It's always valuable to understand the roots of current political movements. Second, it does provide a few significant and memorable challenges to Rawls' view. Though it is disjointed and poorly constructed, it does provide a few brilliant insights on Rawls' assumptions about people and their relationship to property etc. Finally, it is the best construction of this political model I've ever found. His ontology is far far more sensible than anything the pseudo-philosopher Ayn Rand rolled out.
Nozick himself was a respectable and brilliant philosopher when he was doing formal logic or epistemology. However, he really cannot do political philosophy worth a damn. Rumour has it that in his later years, he actually came to distance himself from this effort. It is historically significant, and provides some insight, but the book itself is a confusing, fallacious and lazy account of the state. 

A classic work of genius!

Interesting counterpoint to Rawls's Theory of Justice. Together, they explore the questions of what is just, what is proper role of the state, and what are our obligations to each other.

Experience Machine - pages 42-45

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Review: Anarchy, State, and Utopia

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