Ai Weiwei invited visitors to write postcards to prisoners around the world. This book delves into those postcards' lasting impact. Five former prisoners reflect on the experience of receiving hundreds of postcards. A statement by Ai Weiwei contextualize this extraordinary project. Photographs from the exhibition show visitors and the postcards they wrote. The book also includes a guide to defending human rights and four pre-addressed, tear-out postcards, inviting readers to get involved and send personal messages to current prisoners of conscience.