This book isn't an introduction to postmodernism (PM). There are several introductions to PM on Amazon if that's what you want. Rather, its task could be described as turning some of the techniques of academic PM on its founders - Foucault, Derrida, Lyotard, & Co. The title could have been "Unmasking Postmodernism" because Hicks does so with devastating effect.
I have read several hundred books on philosophy from Plato to the present and I cannot think of one that I consider to have been more clearly written than this. The exposition is admirably jargon-free and straightforward, although some terms might be unfamiliar to some folks. This is the only book in many years that I began re-reading and marking up as soon as I had finished reading it the first time - I think it's that good.
It's important to distinguish between PM in the arts, which is largely an aesthetic trend, and academic PM, which exists almost exclusively in some humanities departments in the universities and identifies with particular epistemological and linguistic assumptions. This book is concerned with the latter group and Hicks provides a well documented case for the following historical sequence:
1) Leftist socialists had traditionally believed that reason and facts would show the superiority of socialism - theoretically, morally, and economically.
2) Academic PM's creators were all leftist socialists around the time that leftist socialism was failing - theoretically, morally, and economically (1950s on).
3) The reaction of leftist academic socialists to this wasn't to accept that they had been wrong. Instead, they availed themselves of recent developments in epistemology and linguistics as a pretext for dismissing reason and facts.
4) They then proceeded to impose leftist socialism on students from behind this mask.
This reaction parallels the Counter Enlightenment movements beginning over 200 years ago that were trying to save room for faith against the advance of science.
I was particularly interested to see Hicks point out the similarities between the tactics of creationists (anti-evolutionists) and PMs. I've been engaged in a running debate in print with a group of creationists for over a year and the similarities are striking and revealing. Academic PM definitely has a cult aspect to it; the movie "Invasion of the Bodysnatchers" comes to mind. American philosopher John Searle once remarked that French PM philosopher Jacques Derrida's work is the kind of stuff that gives bulls**t a bad name.
Some people will say that Hicks is a Randist and that he's merely criticizing PM from that perspective without understanding it. That's a knee-jerk PM tactic - if you disagree with us, you don't understand us. I'm not a Randist, nor am I particularly sympathetic to Rand, yet I didn't feel a Randist presence in the text other than to the extent that Randists still think reason has value and that all opinions are not created equal.
Hicks ends appropriately by telling us that because the Enlightenment project remains unfinished the PMs will be able to carry on as though that project has failed. It could be that the final refutation of academic PM will entail a significant advance in the completion of the Enlightenment project, although it will almost certainly be an updated conception of that project.
There is a lot more value in this book than what I'm reporting here, including a wonderfully illuminating account of the philosophical trends that led to PM and an inventory of the rhetorical tactics used by PMs, so I strongly recommend getting it in your hands ASAP.