The Salvation Army has now been around for more than one hundred and fifty years, having celebrated its sesquicentennial in 2015 with an International Congress in London. Over the years both the Army and the world in which it appeared have changed beyond recognition. This is a good time for the movement to stop and look back—not just to celebrate, but to see where it is today. The Army has not evolved in isolation from the world. Bringing its own history with it, it nevertheless belongs to the twenty-first century world as much as William Booth's little East End Mission belonged to nineteenth-century London. This book attempts to explore the interaction between mission and world as it has impacted the Army's beliefs and practices as well as the place it now occupies in the wider world. This critical and analytical study may also be of interest to those beyond the Army's ranks who would like to learn more about this remarkable organization.