(Again, I feel guilty for such a short review, but aside from lack of time, who am I to say "what the text is saying"?)
Zizek refers to this work as his magnum opus. This is a curious remark for a few reasons. For one, the book does not come across as "climactic"; neither does one envisage a future decline in either productivity or quality in Zizek's writings. Just based on memory, this book is Zizek's longest and most sustained single engagement, but that fact in itself is not particularly relevant. It is undeniably one of Zizek's better books, but not an absolutely singular occurrence in his oevure (such an occurrence would have to be phenomenal).
Needless to say, the reader needs to come to this work with a background in Hegel and Lacan (as well as others, but these are the central presupposed figures). Zizek has been criticized for merely "regurgitating" Lacan or "applying" Lacanian ideas to various topics. This criticism is a little unfair, but it's also true that in this particular work, Zizek tends to string together a series of readings of various texts (which of course includes films, books, thinkers, novels, poems, and even Schumann's Humoresque). Zizek is usually insightful in his readings, even if he occasionally takes tendentious liberties and occasionally falls into obscurity; he is always provocative, however, even if one disagrees with his readings. Some reviews have faulted Zizek for making "too many" references. Although Zizek occasionally cites an obscure author (better known to Europeans than Americans), most of Zizek's texts are familiar to anyone reasonably versed enough in academic and popular culture at least to be able to get the point of a reading even if one has never seen Chaplin's City Lights. Zizek never *simply* refers to something by saying something exasperating (like some other academics) like "Adorno makes the point more emphatically when he claims, with Ibsen, that forms of moral purity are often nourished by a 'hidden egoism.'" At least Zizek explains the comparison or point he is trying to get across. In any event, Zizek writes in a way that demands breadth of knowledge from his readers, but in a way that is not merely an exercise in virtuosity.
On the other hand, one problem with this text is that the argument tends to get lost by virtue of the fact that Zizek moves from the reading of one text to another text such that it feels like all he is doing is either giving examples or arguing by a series of analogies. While there is nothing inherently wrong with analogical thinking, the problem is that it can be easy to miss the point. Zizek is most certainly not just giving examples, but the narrative tends to get buried under the readings.
These readings, however, traverse the gambit from the usual Kant (including an ingenious reading of his ethics), Hegel, Nietzsche, Marx, and Lacan to Heidegger, Kafka, Mozart, Kierkegaard (problematic but interesting), Bernard Williams, Henry James, Wordsworth, Damasio, and Badiou (his most recent interlocutor).
The central idea is, of course, that of parallax, but it is easy to miss the point here. Zizek is *not* primarily interested in the perspectival aspect of parallax. While this feature of parallax often emerges in this discussions throughout the book (for example, he speaks of the political parallax in this way: "all [that] is needed is a slight shift in our perspective, and all the activity of "resistance," of bombarding those in power with impossible "subversive" (ecological, feminist, antiracist, anti-globalist...) demands, looks like an internal process of feeding the machine of power, providing the material to keep it in motion"), the "shift in perspective" is not the main point.
The main point is that when we take this shift in perspective, what becomes evident is the *parallax gap*, which is irreducible to either one of the two perspectives in parallax or even to perspective itself. The gap is the mark of the *noncoincidence of the One itself*. Here Zizek enters into the ontological debate between Deleuze and Badiou by proclaiming that "the pure difference is itself an object. Another name for the parallax gap is therefore minimal difference, a "pure" difference which cannot be grounded in positive substantial properties". (And, of course, we must turn to Lacan for the full importance of this: 'L'objet petit a' is the pure parallax object.)
It is this absence in the center of parallax that is key to Zizek's so-called "rehabilitation of dialectical materialism". The parallax is the key to his "materialist theology" in chapter two, but the relationship of parallax to (Hegelian) dialectics is precise: the parallax does not allow for synthesis to occur. In fact, it seems like Zizek has either given up on the very idea of synthesis or is arguing that synthesis entirely misses the point.
The encounter with Hegel thus continues Zizek's prior work, and he (more or less) explicitly updates his arguments in The Sublime Object of Ideology and The Ticklist Subject. Continuities, however, are apparent from other works such as Tarrying With the Negative (which is among my own favorites of his works and probably his most "theoretical" work despite the claims of The Parallax Gap).
What I personally found the most interesting in this book is the idea of pure ontological difference in itself--i.e., the very idea of parallax which is rather underdeveloped in the work. (Perhaps Zizek is simply relying on Badiou's kind of ontology, but this itself is not unproblematic.) Zizek devotes only a few pages in the first chapter to it before mobilizing the concept of the parallax in his readings of ontology, epistemology, and politics. (Of the three, the second seemed the weakest and Zizek's argument about the irreducibility of brain processes and conscious experiences added little to current debates in the philosophy of mind, even if the text was illuminating in some parts. In this light, chapter three was more interesting than chapter four, even though it was the latter on which Zizek placed the most argumentative emphasis.) Hence my first reason for this rating: the most interesting idea of this book from a philosophical point of view was underdeveloped before it was deployed (even if the critical exercises were stimulating). (Or, another way of saying this is that Zizek is at work in this book as a critic and not a philosopher.)
The other main reason for my rating is the surprising number of typographical errors throughout the book. These include misspellings, missing words (such as the one I added in brackets in the quotation above), some formatting errors, and so on. Some sources are also cited as "unpublished" or "forthcoming" which are indeed published (one such work, for example, was published in 2005, which should have been enough time for the printing of The Parallax View).
I used the word "provocative" several times in this review, and I did so consciously: it seems the best adjective to describe this work as a whole. The work "calls forth" insights in the reader in just about every page, even if they are not the insights Zizek is communicating. There are moments when obscurity muffles this call, but on the whole it is not a waste of time for anyone who thinks Zizek is on to something (on the other hand, if you don't think that, this work will not convince you otherwise).