'The Enemy Within' outlines the history of state surveillance in Aotearoa over the last 100 years, with a particular focus on how it has been used to penalise activists working for social change. Like so many others involved in social justice movements, author Maire Leadbeater was subjected to state surveillance during a long life of activism. With the help of archival material, released SIS files, and other formerly secret material, she has been able to examine the depth of state intrusion into the lives of individuals and movements that challenged the social order. An adverse security record not only harmed those directly affected but also denied the community the valuable contributions of highly talented individuals, many of whose stories feature here.This book explodes the myth that our major intelligence agencies, the SIS and the GCSB, work in our interests. They were set up to work closely with our traditional allies and the 'Five Eyes' network. Instead of protecting us from foreign interference, they have compromised our sovereignty and our ability to pursue an independent foreign and defence policy. Tellingly, on the few occasions when New Zealand has experienced terrorist crime, it has been the police working openly and accountably who have taken the key role. Thought-provoking and insightful, The Enemy Within mounts the argument that unaccountable intelligence agencies harm our democracy and should be disbanded, and their work left to the police.