This is actually 3.5 stars, but I rounded up because the book is worth reading.
Some editions have a rather terrible description, but here's what it actually includes:
A powerful criticism of analytic metaphysics, which, even if one disagrees with it (as I do), should be considered by anyone interested in the topic.
An analysis and history of empiricism.
An analysis of what holding a philosophical position actually consists of (van Fraassen concludes that philosophical positions can be "stances" instead of explicit doctrines)
A critique of physicalism and materialism as an example.
A superb criticism (I think it's a refutation) of Quine's program of naturalizing epistemology.
An existentialist analysis of the psychology of theory change in scientific revolutions (this book is a work of analytic philosophy, but it includes some Continental themes)
Quite a bit about van Fraassen's "voluntarist epistemology", which is extremely pragmatic. These parts discuss Pascal's Wager.
An interesting criticism of epistemological theories that try to construct all knowledge from a few basic principles (he calls such theories "foundationalist", but that's a bit misleading)
A somewhat mediocre analysis of the nature of science.
A truly regrettable section on religion, which can easily be skipped over.
It's been asserted that this book uses the questionable strategy of questioning naturalism to make the reader more receptive to religion, but that's probably inaccurate. When van Fraassen argues against metaphysical naturalism, he's specifically arguing against the Quinean strategy of analyzing the ontological commitments of scientific theories. He does so because he's criticizing contemporary metaphysics, which he does because he's against metaphysics in general. Those parts never argue for metaphysical non-naturalism, though I believe there is a cliched little argument in the religious section. His refutation of epistemological naturalism specifically refutes Quine's idea that epistemology ought to become cognitive science, and one could argue that his pragmatist picture of epistemology is definitely more naturalistic than, say, Cartesian epistemology.
That being said, the parts on religion are definitely awful and seem to be more or less incoherent with the rest of the book. However, van Fraassen is preaching to the converted and thankfully ignores popular debates about science and religion.
There are also some problems with his criticisms of metaphysics. When he criticizes metaphysical naturalism, his case study does not use a regimented theory, which means that his argument doesn't apply to Quine's specific position. Furthermore, he considers his arguments to have accomplished a refutation of metaphysics in general. However, they make use of metaphysical theses like "scientific theories do not contain clear ontological commitments" or "the word "world" never refers to actual entities and instead specifies domains of discourse". Consequently, his arguments would be self-refuting if they refuted all metaphysics, since they include negative and therapeutic metaphysical assertions.
However, it's not clear that he would have refuted all of metaphysics anyway, since some of his main arguments use case studies. If they are not considered to do such a thing, they still say interesting things about metaphysical methodology. For example, van Fraassen notes that abductive methods in metaphysics suffer from a lack of clearly defined or agreed-upon explanatory virtues, suggesting that a proper epistemology of explanation is needed prior to any such metaphysical theorizing.
Nonetheless, I still found this book extremely thought-provoking. Van Fraassen has many good arguments, and even when I disagreed with them, coming up with criticisms was a fascinating intellectual exercise.
The argument against Quinean naturalistic epistemology essentially notes that if such epistemologies contained descriptions of how we rationally draw conclusions (and they would have to), then they would have to label us irrational if we rationally rejected those descriptions because they were refuted during a scientific revolution.
Although this book isn't particularly difficult, to understand it one definitely has to have read Quine, understood current trends in epistemology and metaphysics, and understood Kuhn's philosophy of scientific revolutions and the resulting historicist turn.