This award is made as part of the FY 2013 Mathematical Sciences Postdoctoral Research Fellowships Program. Each of the fellowships supports a research and training project at a host institution in the mathematical sciences, including applications to other disciplines, under the mentorship of a sponsoring scientist. . The title of the project for this fellowship to Theodore Johnson-Freyd is "Combinatorial and Topological Constructions of Batalin-Vilkovisky Quantum Field Theories." The host institution for the fellowship is Northwestern University, and the sponsoring scientist is Dr. Kevin Costello.