In Policing Empires, Julian Go offers a postcolonial historical sociology of police militarization in Britain and the United States. He tracks when, why, and how British and US police departments have adopted military tactics, tools, and technologies for domestic use. Using both secondary and primary archival sources, Go reveals that police militarization has occurred since the very founding of modern policing. This book thereby unlocks the dirty secret of police militarization: Police have brought the imperial boomerang home to militarize themselves in response to perceived racialized threats from minority and immigrant populations.