Why The Stack?an accidental megastructure?is both a technological apparatus and the geopolitical model of our times. A tenth anniversary edition of the comprehensive political philosophy of planetary-scale computation, with a new preface from the author.What has planetary-scale computation done to our geopolitical realities? It takes different forms at different scales?from energy and mineral sourcing and subterranean cloud infrastructure to urban software and massive universal addressing systems; from interfaces drawn by the augmentation of the hand and eye to users identified by self?quantification and the arrival of legions of sensors, algorithms, and robots. Together, how do these distort and deform modern political geographies and produce new territories in their own image?In his groundbreaking survey The Stack, Bratton anticipated the changes we see around us now. He proposes that different genres of computation?data centers, AI, cloud platforms, mobile apps, logistics, protocols, automation, robotics?can be seen not as different species evolving on their own, but as forming a coherent whole: an accidental megastructure called The Stack that is both a computational apparatus and a new governing architecture. We are inside The Stack, and it is inside of us. In an account that is both theoretical and technical, drawing on political philosophy, design theory, and computer science, Bratton explores six layers of The Stack: Earth, Cloud, City, Address, Interface, User.