Black Lives Matter began as a hashtag when Alicia Garza wrote what she calls ‘a love letter to Black people’ on Facebook. But hashtags don’t build movements, she tells us. People do. Interwoven with Garza’s experience of life as a Black woman, The Purpose of Power is the story of how she responded to the persistent message that Black lives are of less value than white lives by galvanizing people to create change. It’s an insight into grass roots organizing to deliver basic needs – affordable housing, workplace protections, access to good education – to those locked out of the economy by racism. It is an attempt not only to make sense of where Black Lives Matter came from but also to understand the possibilities that Black Lives Matter and movements like it hold for our collective futures. Ultimately, it’s an appeal to hearts and minds, demanding that we think about our privileges and prejudices and ask how we might contribute to the change we want to see in the world.