Let’s face it: Recent years have been tough on optimists. Hopes that the Internet might bring people together have been crushed by the ills of social media. Is there a way back?

As head of TED, Chris Anderson has had a ringside view of the world’s boldest thinkers sharing their most uplifting ideas. Inspired by them, he believes that it’s within our grasp to turn outrage back into optimism. It all comes down to reimagining one of the most fundamental human virtues: generosity. What if generosity could become infectious generosity? Consider

• how a London barber began offering haircuts to people experiencing homelessness—and catalyzed a movement

• how two anonymous donors gave $10,000 each to two hundred strangers and discovered that most recipients wanted to “pay it forward” with their own generous acts

• how TED itself transformed from a niche annual summit into a global beacon of ideas by giving away talks online, allowing millions access to free learning

In telling these inspiring stories, Anderson has given us “the first page-turner ever written about human generosity” (Elizabeth Dunn). More important, he offers a playbook for how to embark on our own generous acts—whether gifts of money, time, talent, connection, or kindness—and to prime them, thanks to the Internet, to have self-replicating, even world-changing, impact.