'Girls should never be afraid to be smart.' Emma Watson The Spice Girls knew it way back in the day, and we still know it: girls rock. Who run the world? Rebel girls, that's who. This book is perfect for any time you're in need of a shot of wisdom to remind you that independent women kick ass. With quotes from Oprah, Malala Yousafzai, Beyonce, Tina Fey, Amy Poehler, Emma Watson, Michelle Obama, Caitlin Moran and many more, this book lets the world hear us roar.