While I found Mr. Soja's book educational and somewhat enjoyable, I also found a lack of incorporation (which might imply a lack of understanding) of many aspects of postmodern innovations. I do not claim to grasp the genre/concept entirely, but I think that many readers will find that Soja stops his thinking short of where it might be expected to go.
There is a feeble, and seemingly ad hoc, literary structure that the introduction explains as isomorphic of the fragmented spatiality of postmodern geography. I don't buy that explanation. I read the book from beginning to end and did not feel like I was passing through mini-paradigms or multiple perspectives. The first three chapters are exceedingly repetitive and the rest of the book only moderately so; it is perhaps for this reason that the author suggests picking up at any point in the book. Again and again the legacy of traditional academic Marxism is critiqued for ignoring spatiality, yet Soja only asserts the necessity of a fundamental incorporation of space into social theory in a brief portion of the first chapter. What's more, this brief argument is based entirely on the scholarship of other theorists and does not even consider possible objections. As such this book will not, if you are reading it thoroughly, convince you to equally incorporate space and time but only that "everybody else" in geography is doing it.
A summary of recent trends in geography is by no means a poor basis for a book. I was very unfamiliar with (what used to be) contemporary issues in geography, and after reading Soja's work I feel familiar with many theorists as well as the discipline's terminology. Brief aside: Soja absolutely loves academic jargon, so be prepared with a dictionary at hand if you are not a serious academic. But a summary of trends is not what the author makes out his book to be. He calls it a "reassertion of space in critical social theory", yet his rhetorical structure assumes the truth of his position and subsequently presents facts that correlate with this assumed truth. This does not mean that I think the author is wrong about space, simply that he makes a pretty weak assertion.
I learned about a lot of things from this book: Marx's writings and Marxism, Henri Lefibvre, existentialism and its contingence upon the constructed mental space that seperates the individual from the rest of the world, social theorists and geographers in the 70s and 80s that began to incorporate the socio-spatial dialectic into their work, and (unfortunately) that "postmodern" geography is just an equally social, spatial, and chronological form of Marxian analysis. If postmodernism is a rejection of the metanarratives of modernism (as it is in part according to Lyotard) then the type of geography that Soja is describing is not very postmodern. "Postmodern Geographies" questions but ultimately deifies Marx, and in doing so celebrates the inter-era significance of one of the most rigid and deterministic metanaritives.