Certainly not as uninteresting as other reviewers claimed. One of few actually good resources on understanding introversion, though it does seem like it may benefit someone coming to terms with their nature more than someone who already knows (for those, I recommend Quiet by Susan Cain instead).
There is a ton about mindfulness but it's clear this was included based on what worked for the author, and is not a universal claim that 'all you need to do is meditate and stay in the present and suddenly all your issues will be cured!' It's easy to skim past those bits if the mindfulness movement doesn't really do it for you.
The best thing about this book is that, while it does include tips on turning on your extrovert when you need to, it doesn't tell you that you need to act to survive. Quite the opposite: the overall purpose seems to be to remind you that just because your nature goes against your culture doesn't make it wrong. AKA, you're awesome and it's time to accept that. Great tips on asking yourself the questions you are afraid to answer as you begin to stand up for yourself and your needs.