This chapter maps secularism as a culture, using the example of Berlin. It takes the reader through all of the venues that provided materialist monism and establishes their relationship to the socialist milieu. It begins in Free Religion, and then analyzes the city’s chief popular scientific institutions. It looks in detail at the offerings of each to illuminate how monism was communicated. This chapter argues that despite political polarization among the secularist organizations, there was nonetheless a great deal of ideological and personnel coherence across the secularist spectrum