This book was recommended to me by a former manager at Fleming College on my 2nd day of work, when he realized that I may not actually be the glaring extrovert I appear to be on the outside (side note: an instructor at Seneca College suggested that I may in fact be an ambivert, given that I tend to fall right around the line distinguishing introverts from extroverts on the Myers-Briggs scale - the quiz on Cain's website would also see me classified as an ambivert).
In this book, Cain introduces notable introverts in history, and explains how their preference allowed them to make such significant contributions over time. She also explores how some of the 'typical' traits of introverts can be both a gift and a burden, especially in North American or European societies that so value extroversion. Most importantly, Cain identifies some of the challenges faced by introverts and extroverts alike in the workplace, in romantic relationships, and even in parenting.
One thing I liked about this book is that it wasn't 'extrovert bashing', in the sense that Cain didn't focus on how society is wrong for expecting all individuals to act a certain way. Instead, she explains some of the errors made by individuals of both types in certain situations and how they can meet in the middle to create/strengthen productive, supportive, and loving relationships.
As someone who can identify with both 'types', I found this book helped explain some of my own behaviours, as well as the reactions of others when I exhibit more of one than the other. Given that one third of all individuals identify as introverts, I think this book is a great read for managers who wish to support and encourage the more 'reserved' members of their teams; spouses looking to better understand their partners; parents who wish to help their children thrive without forcing them into a mould; or any individual wanting to understand the people around them.