This book set out with several aims. It sought to show the extent to which the British monarchy and British monarchism mattered during the First World War. Monarchism was not unimportant or mere rhetoric; the monarch was not a token figurehead. In fact, it was one of the central British belief systems of the age. More broadly, throughout Europe and its empires monarchism, like socialism or communism or liberalism, was a significant ideology in the public sphere. This book has also aimed to contextualise monarchism as a historically contingent phenomenon, manifesting in different ways in specific historical moments. First World War monarchism, it has shown, merits being assessed not only as a political framework but also as a distinct belief system which existed during the war period and its aftermath.