The Fear of Erring, a combination of thick ethnography and an ethnopoetic storyline, illustrates how mistrust, ignorance, and imagination govern the everyday work of personnel in Argentina's criminal justice system. The book shows that Argentina's justice system faces public suspicion and a tense atmosphere of competition and mutual mistrust among employees. It provides evidence of widespread fear among legal professionals of being deceived and making erroneous decisions based on manipulated information. Rational methods of generating knowledge often hit their limits, confronting employees with impenetrable ignorance. The detailed description of bureaucratic life demonstrates that legal professionals resort to imagination and speculation, yielding insights into their moral positioning. By focusing on these imaginaries, the book reveals unnoticed routines and functions of the justice system that shape legal processes, decision-making, and the institution's image. The book's discussion on mistrust, ignorance, and imagination extends beyond Argentina, addressing key questions about social cohesion, knowledge bases, and perspectives on the past and future in current social and global debates.