This is a collaborative book with chapters written by different psychologists, but all under the umbrella of unconscious processes. As I write this, the two previous reviewers, Dr Richard G Petty and Jim Snyder have both written fine reviews whose content I'll try not to repeat here.
What I'll do instead is mention some of the insights I found in the book. I should say first, that some of the chapters involve a familiarity with psychological concepts that most of us don't have, but quite a number of chapters can be understood by people, like me, who are coming at the unconscious from other fields: sociology, business, cultural anthropology, education, etc.
With the emphasis here on what happens unconsciously, you might wonder why we have a consciousness at all. From an evolutionary standpoint, why did we develop one? One answer is that we need it to learn new things. But having learned them, the unconscious mind will take over their processing. So, in chapter 2, John Bargh notes: " "It would be ironic if... the evolved purpose of consciousness turns out to be the creation of ever more complex nonconscious processes."
In another chapter, Lillard and Skibbe note a cultural difference in what they call Spontaneous Trait Inference. That is, when we observe something, we ascribe a reason for it. (As cultural anthropologist Brosnan Malinkowski noted decades ago, the assumption of cause and effect is cross-cultural.) But Asian cultures are more apt to ascribe a situational reason, while Americans are more apt to ascribe an individualistic reason. (This is something I've noticed in political liberal vs political conservative attitudes. Looking at someone with a problem, such as being unemployed or using drugs, do you ascribe his situation to external causes or to a personality defect?) Food for thought.
Choi, Gray, and Ambrady discuss research in "unintended" communication and perception. They find, for instance, that we have built-in lie detectors -- we unconsciously pick up cues when someone is lying. This process is certainly imperfect, but it turns out that it works better than when trained interrogators try to detect lies. Apparently, bringing the conscious mind into the picture actually worsens the results. Interestingly, also, those trying to detect lies consciously are more confident of their results than the rest of us doing it unconsciously.
In that same chapter, the authors note research that indicates teacher-student expectations "leak" outside of verbal channels. That is, if teachers expect more from some students, that gets communicated to the students even if the teachers don't verbally indicate so. And it affects student performance, as we all tend to try to work up to expectations, unconsciously.
Chartrand, Maddux, and Lakin note that researchers have found a link between perception and doing. And that we have a very strong need to belong and affiliate within our own culture. Put that together, and it explains unconscious mimicry. Without our knowing we do it, we mimic the verbal patterns, language, and bodily movements of someone we're with and have a bond with. And this bidirectional mimicry increases that bond. While, on the other hand, research indicates that if we're with someone who was purposely told not to mimic us, we take an unconscious dislike to that person.
There are way more insights in the book, but I hope that provides a flavor of the topics covered. Certainly not an easy read, but one that definitely pays off the reader.