People organizing prison books programs have quietly gathered in basements, storage spaces, and the back rooms of secondhand bookstores for the last seventy years, reading letters written by incarcerated people and sending books in return. This diffuse and nonhierarchical movement operates on shoestring budgets with donated libraries in thirty states, and yet, there is little awareness of this long-standing social movement. This book contains essays that explain the need for prison book programs and offer advice on how to establish or become involved with prison books programs, as well as shedding light on current challenges. While mass incarceration can make people feel powerless, this book details how ordinary people can organize and intervene in the largest imprisonment the world has ever known. The editors of this book hope it will inspire more people to realize that everyone has the power to treat each other differently and to foster a culture of care over cruelty. Royalties from the sale of this book will go to the Martin Sostre Memorial Prison Books Fund which grants money to prison book programs that send free literature to incarcerated people annually. Martin Sostre won several foundational prison censorship lawsuits while incarcerated and opened the door to sending books inside.