Chapter 4 reviews the way in which CPI is organized internally, based on evidence from online data, open observation and face-to-face interviews. Specifically, it discusses how strategic choices concerning group organization have allowed CPI to acquire the financial, human and symbolic resources that have contributed to its survival and expansion. First, the chapter presents the formal hierarchical structure of CPI, and its territorial and thematic organization (4.1). It then moves on to the rules governing leadership, personnel selection and decision-making (4.2), recruitment (4.3) and modes of engagement into CPI – with special attention on youth, women and football fans (4.4). The empirical analyses indicate that CPI invests simultaneously on formal organizational party structures and on less formal modes of participation inspired by social movements, that have crucially contributed to sustain CPI’s recruitment and activist practices. In conclusion the chapter argues that the high profile that CPI currently enjoys rests, at least to a certain extent, on its hybrid organizational configuration.