Militant Acts presents a broad history of the concept and practice of investigations in radical political struggles from the nineteenth century to the present. Radicals launched investigations into the conditions and struggles of the oppressed and exploited to stimulate their political mobilization and organization. These investigations assumed a variety of methodological forms in a wide range of geographical and institutional contexts, and they also drew support from the participation of intellectuals such as Marx, Lenin, Mao, Dunayevskaya, Foucault, and Badiou. Marcelo Hoffman analyzes newspapers, pamphlets, reports, and other source materials, which reveal the diverse histories, underappreciated difficulties, and theoretical import of investigations in radical political struggles.