The volume establishes an ethical framework for the identification, analysis, and resolution of ethical challenges that arise from the uses of artificial intelligence (AI) in defence, ranging from intelligence analysis to cyberwarfare and autonomous weapon systems. It does so with the goal of advancing the relevant debate and to inform the ethical governance of AI in defence. Centring on the autonomy and learning capabilities of AI technologies, the work is rooted in AI ethics and Just War Theory. It provides a systemic conceptual analysis of the different uses of AI in defence and their ethical implications, proposes ethical principles and a methodology for their implementation in practice. It then translates this analysis into actionable recommendations for decision-maker and policymakers to foster ethical governance of AI in the defence sector.