The title of the book gives the impression that it's a self-help book. It's more of a psychology book explaining how people can make mistakes, think they are right, and honestly believe that. A good example is false memories. How often have you said, "I could have sworn I did that." You see the event in your head, yet evidence shows it didn't happen. You rationalize it ("someone must have moved it") instead of accept the most obvious answer ("I was mistaken in thinking that I did it").
The books goes even further into big mistakes that people make and refuse to admit, such as in the criminal system where suspects are locked away for years ("I know he's the rapist so I'll interrogate him for hours until he finally confesses") until DNA finally proves their innocence. Fortunately for most people, they are not making mistakes that means life and death. The book contains many extreme examples. Still, this is great book to read to understand and recognize your own mistakes. For example, maybe a friend asked for a favor and you said no. Initially you felt a little guilty for saying no. Then you start justifying the answer, "She wouldn't have helped me if I had asked for a favor. She's always looking for someone to do her work." So that guilty feeling goes away. It's a rude awakening to realize how your feelings have completely changed -- you went from feeling a little guilty to thinking your friend is selfish and lazy.
This book is a balanced blend of scientific data and storytelling. The author explains how your brain works (e.g., it's easier to drive and talk at the same time, but not read email and listen to a conversation). You learn what to do -- minimize multitasking as much as possible and don't do it at all when the two tasks rely on the same region of the brain. The author then takes you through the problems faced by two fictitious characters, Emily and Paul. The same scenes are replayed following his advice. Although the scenarios are fictitious, they represent common situations at work and how they can be handled poorly (as we react without thinking) or effectively (stay calm and re-direct it to a positive outcome). The pattern in the book of data, scene, and replay of scene reminds you to slow down and think, especially as you see how Emily and Paul in their rush to get things done, they end up doing rework to fix their problems. I think this is a book you can read again to identity bad habits you continue to do and work on those.
The book lacked a tight integration of all the concepts into a step-by-step program. It approach varied -- sometimes it was about "try mediation... do this...." Then it switched to information, like how your brain works and how your willpower can be depleted. Then there's a little of both, like good behaviors are used to justify bad behavior ("I exercised today so I'm going to reward myself with some chocolates"). I think you need to read only one chapter a week to absorb the information and practice it for a few days before moving on to the next chapter.
Markman lays out some useful strategies for improving your thinking. The tips aren't pulled out of thin air, as they are in some books on the topic; they're based on Markman's research and the research of others in the field.
One important technique is to evaluate your understanding of a topic by trying to explain it to yourself. Be honest in acknowledging where your explanations break down or gloss over a difficulty; then work on those until you *do* get them. (I've seen this suggestion in other contexts, where it's been described as the "Einstein technique," though I'm not really sure how that name came to be associated with it.)
Another important point is to recognize your mind's limitations - not just *your* mind, but *everybody's*. The human brain, according to Markman, can usually only process three distinct features of an experience; so he recommends regularly summarizing what you've learned by listing three main points. With careful selection, it's possible to use those points as triggers to a wider array of knowledge: the brain is like a fishing net, where latching onto one point can lead you to others. (My analogy, not Markman's.)
Markman offers some useful cautions as well. Especially in group settings, it's important to pause before making a final decision: feeling the visceral "click" when smart thinking leads to a breakthrough can be physically pleasurable; but you shouldn't let that glow influence your evaluation of the breakthrough. Wait a couple of days before you act on it.
Sean Pratt is a particularly effective narrator for this kind of material. He's done many titles for Gildan Media, and their titles in the self-development or "science for daily life" area tend to be a cut above the norm.
If you like this book, you may also enjoy "Five Elements of Effective Thinking" by Michael Starbird and Edward Burger. There is some overlap between the books; I found both of them helpful.