Rainer is a German practical theologian and urban missiologist. He is also a trained journalist and pastor. After his undergraduate studies in geography (minors in communication studies and Spanish) at the Free University of Berlin, he researched migration issues on the Mexican-American border and came to faith in Christ. He studied theology at NL Theological Seminary (now Rhineland School of Theology) near Cologne. After several years in ministry in Berlin, where he worked in Christian media and – with his wife Christine – founded a missional inner-city project, he did postgraduate studies at London Bible College/Brunel University with further studies at Humboldt University of Berlin. Rainer has founded and co-founded a number of urban ministries and projects, including a social ministry for Muslim children and youth, a Christian gallery and arts ministry, and an urban education initiative. He co-led two church plants and is founding director of the Berlin Institute for Urban Transformation. He is also dean of a graduate program in urban missiology at Rhineland School of Theology, serves as a lecturer in the Network for Education and Research in Europe, and has supervised and examined German-speaking MTh students at the University of South Africa. He is part of Together for Berlin, an interdenominational Christian network, and is one of the chairs of the European Evangelical Alliance Cities Network. Rainer has written or edited some books and published a number of articles.