The Research Training Group builds on an established and very lively collaboration between the Departments of Mathematics and Physics and the string theory group of DESY (http://zmp.desy.de). It is embedded in a larger research environment consisting of the Collaborative Research Center SFB 676 "Particles, Strings and the Early Universe" (http://wwwiexp.desy.de/sfb676) and the Cluster of Excellence "Connecting Particles with the Cosmos" (http://lexi.desy.de). The Research Training Group aims at educating mathematicians and mathematical physicists with basic knowledge in string theory and quantum field theory that enables them to participate actively in cutting-edge interdisciplinary research. Research topics include differential geometry connected to supersymmetry, three-dimensional topological field theories, mirror symmetry, string topology and holomorphic curves, algebraic and arithmetic structures in perturbative quantum field theory and higher categorical geometry and homotopical methods for string backgrounds. Students connect and broaden their individual Ph.D. projects by lectures of resident and guest scientists, working seminars, block courses and exchange programs. All activities take place in English.