There was a bit of a dichotomy with this book for me. On one hand, I wanted to love it, and it had all I needed for 4-5 stars from a writing standpoint. It is extremely well written and the author just kind of sweeps you up in the book, which is rare to me in a nonfiction and research-heavy book. On the other hand, though, the content left me more confused that I think it should have. Don't get me wrong - there's a lot of good stuff in here and plenty of studies to back up the author's arguments. But I'm an extrovert and married to an introvert, yet found a lot of the connections she made didn't apply (introverts are more sensitive, but that would be more me than my introvert spouse, things like that). It left me confused about whether I truly am an extrovert and vice versa, or if there really isn't such a stringent connection between these things. So, with feeling a bit unsettled at the conclusions, I have to give this book 3 stars.