I've just finished reading Blink: The Power Of Thinking Without Thinking by Malcolm Gladwell. This was a medium length book but it took a surprisingly short time to read: it's light and breezy, a very easy read. Which might be surprising, as it purports to be a study of an issue of psychology of considerable depth, but it still zips by with little effort and less time.
Most of the book is entertaining, engaging, and entirely unchallenging, since it consists of a series of anecdotes and real-world examples, told in an easy and enjoyable style, of the ways in which our subconscious perceptions and thoughts affect us where we usually don't notice. That's what 95% of the book consists of, and good thing, too, since that's where it shines. Had this been heavy or slow-going it might not have been worth it, but easy as it is, it's fascinating enough to bear the weight of reading it. Think of it as a smorgasbord of isn't-that-interesting moments on a common theme.
The author, however, probably intends it as an insightful commentary on human nature that will shock and amaze, and I suppose for a lot of people it is exactly that. But, without meaning to sound too arrogant, that's only the same way the "what is reality?" twist of The Matrix astounded so many people: these were people who had, previously, lived under rocks, and never heard of the idea before. (Aside: I know a lot of people loved The Matrix for reasons other than its philosophy, and these comments don't apply to those people. I'm only astonished by people who think it was a seriously innovative concept, rather than, as the creators intended, "an excuse to have kung fu fights with robots.")
The thing is, sure, anyone who's taken a semester of psychology, or pondered the nature of the creative arts, or investigated artificial intelligence, or studied epistemology, or even asked themselves why they like one band and not another, or one dish and not another, or one painting and not another, any of these people will have at least bumped into the question of how much of our thoughts and perceptions are happening at a level beyond our awareness. Only a slightly deeper consideration will have led us to conclude that in many cases, our professed thoughts are at best pretexts to justify unconscious ones. But there must be people who haven't thought about this.
I think the author probably also imagines he's not just pointing out that this is a fact of human existence, but also that he's shedding light on how it works, what it can and can't do, what effects it has on us. And certainly by time you're done with the book you will have some new ideas about those things, very likely. But those all come from the anecdotes and examples. His commentary offers no fresh insights; at best, it serves as effective segues between the real-world stories that tell the real story. He might also imagine it gives us tools for how to tap that part of our minds, but really, in the end, it just hints that you can learn to harness it with practice... which is no doubt true, but it hardly needs a book to tell us that.
If you've never encountered this idea, read Blink, stat. If you have, read it anyway, just to find a lot of elaboration in the examples. Either way, the fact that it will only take a few hours is enough reason to make it worth those hours.