The fifth and final volume of the Canadian State Trials series examines political trials and national security measures during the period of 1939 to 1990. Essays by historians and legal scholars shed light on experiences during the Second World War and its immediate aftermath, including uses of the War Measures Act and the Official Secrets Act with the unfolding of the Cold War and legal responses to the FLQ (including the October Crisis), labour strikes, and Indigenous resistance and standoffs. The volume critically examines the historical and social context of the trials and measures resulting from these events, concluding the first comprehensive series on this important area of Canadian law and politics. The fifth volume’s exploration of state responses to real and perceived security threats is particularly timely as Canada faces new challenges to the established order ranging from Indigenous nations demanding a new constitutional framework to protestors challenging discriminatory policing and contesting public health measures. (Osgoode Society for Canadian Legal History)