We are fast approaching the point of "peak digital", with the continued mass production and excessive consumption of digital technologies set to become a key driver of climate crisis, ecological breakdown and ongoing societal instability. Digital Degrowth is a call to completely rethink our digital futures in these fast-changing times. It explores how degrowth thinking and alternate forms of "radically sustainable computing" might support ambitions of sustainable, scaled-down and equitable ways of living with digital technologies. Neil Selwyn proposes a rebalancing of digital technology use: digital degrowth is not a call for simply making reduced use of the digital technologies that we already have - rather it is an argument to reimagine digital practices that maximise societal benefits with minimal environmental and social impact. Drawing on illustrative examples from across computer science, hacker and environmental activist communities, this book examines how core degrowth principles of conviviality, autonomy and care are already being used to reimagine alternate forms of digital technology. Original and stimulating, this is essential reading for students and scholars of media and communication, sustainability studies, political ecology, computer/data sciences, and across the social sciences.