As the title suggestions, this book is divided into two sections: A guide to wealth, and a guide to happiness.
The Guide to Wealth
Naval has a lot of suggestions on routes to wealth here. It's easy to come up with a bunch of counterexamples to his suggestions or situations where his suggestions wouldn't work, but I there are some truly insightful ideas.
One of the most important relates to leverage. The idea is that you want to do work that has the potential of giving you what I would call "multiplied" returns.
So, for example, any job where you are directly renting out your time for work, such as babysitting, can not give multiplied returns. You are paid X $/hour, and that's that.
In contrast, there are tools like code and media that allow you to get multiplied returns. You can code something once, such as a web app like Quizlet, or make one piece of media, like a YouTube video, and it can be used or consumed an infinite number of times. There is no fixed dollars per hour number you are limited to, so the upside is unlimited. The caveat here is you probably want to be working for yourself for this to work, otherwise whoever you are working for will be getting the outsized returns.
Capital is another, more traditional way to get leverage: Put more money into something, and you can get more money out. It's independent of how many hours on whatever method you're using to make money - whether it's in the stock market, roulette, or whatever.
The Guide to Happiness
This section is largely the fundamentals of meditation, in Naval's words. The core tenets are all there: being present, the uselessness of anger, etc. There are also other sections related to finding purpose in life, values, and more.
While I don't know if Naval presented new concepts here, per se, I still greatly enjoyed reading this section. Reading about meditative principles is always a useful practice; day-to-day life gradually distracts us from those principles and a reminder helps re-ground us. And I think anyone who hasn't already read about the principles of meditation/"enlightenment" will find this section extremely valuable.
Do I Recommend This Book: Yes
This book is packed with useful information that can legitimately change your perspective on life and your behavior. It's bare-bones, in a good way: it's been reduced to the key points, and each one packs a punch. Even if you've read conceptually similar books, it's still an entertaining, easy read that will still teach you something valuable. Give it a go!