"Coupled with the speed and networking capacities of social media, #blacklivesmatter was the hashtag heard round the world. But Alicia Garza well knew that the distance between a hashtag and real change would take more than a single Facebook post to cover. It would take a movement. Garza was a lifelong activist who had spent the previous decades educating herself on the hard lessons of organizing. She started as a kid, working on sexual education...