There's a lot of technical and research-based discussion, of course (which is very thorough), but as a whole it reminded me of how much pressure was thrust upon me as a child to "be more outgoing," "participate more in class," and "speak up." I can't help but wonder how different my early education and entire childhood could have been if teachers and other adults had learned to value quiet leadership, thoughtfulness, and independent work. Susan Cain actually answers much of this and I won't spoil all the details for you. But I will give you a hint: The Extrovert Ideal. Another hint: it's not a thing in Asia....
Cain doesn't advocate for everyone to become introverts. That's not good for society and also not possible (also explained at length in Quiet). What she advocates for is balance, and I agree that a balance of the two within a person and within a society can do great things.
I highly recommend this book to anyone really. Extroverts will understand their friends, families, and coworkers much better (after all, 1/3 to 1/2 of all people are introverts), and introverts will learn to embrace their tendencies and use them for good.
Here's a comprehensive and fantastic TED talk with Susan Cain:
I'll leave you with an awesome "Manifesto for Introverts" that is in the front cover:
1) There's a word for "people who are in their heads too much": thinkers.
2) Solitude is a catalyst for innovation.
3) The next generation of quiet kids can and must be raised to know their own strengths.
4) Sometimes it helps to be a pretend extrovert. There will always be time to be quiet later.
5) But in the long run, staying true to your temperament is key to finding work you love and work that matters.
6) One genuine new relationship is worth a fistful of business cards.
7) It's OK to cross the street to avoid making small talk.
8) "Quiet leadership" is not an oxymoron.
9) Love is essential; gregariousness is optional.
10) "In a gentle way, you can shake the world."- Mahatma Gandhi