Closely examining the work of women in the US and British naval services towards Allied naval intelligence during the Second World War, this book focuses on their contributions during the Battle of the Atlantic and Pacific Naval War, in order to shed new light on arenas of war from which women's narratives are almost always absent. Including personal testimonies from those involved, and surveying a wide cross-section of different roles, Sarah-Louise Miller analyses the work of women at every level and rank in the US and British naval services, and offers a much wider picture of how they assisted the Allied forces behind closed doors. With exploration of the work of the WRNS and WAVES on developing naval intelligence, this book argues that they played a crucial role in the British and American SIGINT systems, and within programs such as those at Bletchley Park and OP-20-G - therefore directly impacting the organisation and outcome of Anglo-American naval efforts. Including analysis of the development of the modern 'kill-chain', Miller also re-evaluates the effect of the 'combat taboo', to demonstrate that the WRNS and WAVES were in fact at the cutting edge of the emergence of modern warfare.