Despite Poland’s decimation during the Second World War, musicians there formed orchestras and performed concerts within days of liberation. Even before hostilities had concluded, audiences flooded makeshift concert halls and revealed a new-found hunger for contemporary classical music. This dissertation asks why musicians in Poland were able to quickly channel trauma into action and examines how their experiences during wartime—whether as performers in Warsaw’s cafés, exiles in the USSR, or refugees from the Holocaust—shaped their subsequent conviction that music could help rebuild a devastated society. To analyze these questions, I study the generation of Polish and Polish-Jewish classical musicians—composers, musicologists, critics, performers, and organizers—who were at the height of their careers when WWII began. I trace the emergent forms of sociality that connected these musicians from the semi-formal associations of the 1930s into the high Stalinist period of the early 1950s. I argue that individual relationships, alongside the politics of friendship more widely, helped to create an artistic milieu that formed the basis for state institutions after 1945. In viewing this history from the ground up, across the span of World War II, I demonstrate that personal experiences of wartime violence catalyzed aesthetics and political organization alike. During the 1920s and 1930s, these musicians shared a conviction that Poland’s musical underdevelopment required widespread action, whether by launching concerts in the Polish backcountry or importing modernist trends from western Europe. During WWII, these same organizations enabled some musicians to survive, while other musicians were forced to take more drastic measures, whether by hiding or leaving occupied Poland. By the early postwar period the paths of these protagonists had diverged, with many (including Zofia Lissa, Tadeusz Ochlewski, Zygmunt Mycielski, and Piotr Perkowski) continuing their work at home. Others, including Roman Palester, Mateusz Gliński, and Tadeusz Kassern, emigrated, even as they shared sympathies for rebuilding. By reconstructing a collective biography of these musicians, I show how their wartime experiences gave birth to heterogeneous visions for Poland’s musical future, visions from which the country’s socialist musical culture was ultimately forged.