I make two points about the role of threats for ethnographic fieldwork in contexts suffused by interpersonal violence. First, the experience of implicit and explicit threats operates as a powerful cultural agent that significantly transforms fieldworkers’ relationship with the field. Second, subjecting oneself to threats can become a central component of the ethnographic immersion into the field. The notion of “threat wisdom” connects these two points by capturing the emerging competence to handle threats and resulting from “becoming threatened,” “becoming threatful,” and “becoming threat wise.” To develop this argument, I discuss insights from my fieldwork with homeless people using cocaine, crack cocaine, heroin, and methamphetamine, in Barcelona.