Always connected—such is the imperative of modern media. But what happens when media cease to function properly? When messages transcend the strict boundaries of 'sender to receiver,' transcend the world of communication itself; messages that proclaim, 'No more messages'? In this book, Alexander R. Galloway, Eugene Tucker, and Mackenzie Wark upend our conventional notions of media and mediation; the authors explore the impossibility of communication inherent in its very nature—an impossibility they call 'excommunication.'