Book excerpt: An Age of Neutrals provides a pioneering history of neutrality in Europe and the wider world between the Congress of Vienna and the outbreak of the First World War. The 'long' nineteenth century (1815–1914) was an era of unprecedented industrialization, imperialism and globalization; one which witnessed Europe's economic and political hegemony across the world. Dr Maartje Abbenhuis explores the ways in which neutrality reinforced these interconnected developments. She argues that a passive conception of neutrality has thus far prevented historians from understanding the high regard with which neutrality, as a tool of diplomacy and statecraft and as a popular ideal with numerous applications, was held. This compelling new history exposes neutrality as a vibrant and essential part of the nineteenth-century international system; a powerful instrument used by great and small powers to solve disputes, stabilize international relations and promote a variety of interests within and outside the continent.