The author outlines a few common pitfalls of the brain that almost everyone suffers from. He uses his vast experience and scientific research to suggest remedies to decreased productivity — including at the workplace — which David consults Fortune 500 companies on. Overall, if you — like me — have read a lot of literature on cognitive biases and habit formation, this book brings nothing new to the table. Remember that the original text was written a while back — even though the new edition was updated in 2020.
Primarily David focuses on how to make the brain more productive. He uses fictional characters, Emily and Paul, to present a variety of situations where they make mistakes — and then, by modifying a few things, they solve the arising issues. I find this particular way of storytelling a bit confusing and somewhat too long (the usual "could this be an essay?")
Firstly, the author makes a case against multitasking. Indeed, we cannot multitask physically — when we try, our mental capacity falls almost to a level of a kindergarten student. So don't multitask, prioritize, and plan. I wrote an article on how I stay productive: "How I launched seven products in 1 year". I also wrote a book that's partially on topic.
Secondly, compare yourselves to you yesterday. If you made any progress, you'd feel better about it by getting a sense of rising status. When humans are better than other humans, they feel better. Yourselves yesterday are also different humans from yourselves today. Go tell yourselves: "I told you so!"
Thirdly, David claims that you'd instead give people indirect feedback to develop solutions on their own, making learning and other processes better. This is not true and has been disproven multiple times by scientists. Feel free to give direct feedback — contrary to what the author suggests. Try not to sound harsh or inhuman. Be kind.
The book is packed with sound (but sometimes outdated) advice. I wouldn't recommend this specific book if you want to increase your productivity (there are a lot of other books that do a better job teaching, in my opinion). Still, it's short enough not to worry about time spent reading or listening to it.