This paper is about a certain type of contested documents (the secret police files known as “informative notes”). It employs a neo-documentalist framework and thematic analysis to examine informative notes on four major intellectuals in communist Romania. The paper focuses on three emerging themes: the power effects that the materiality of informative notes has had, after 1989, on Romanian society; the reasons informers interpreted the writing conventions of this textual genre in radically different ways; and the epistemic aspects of this type of document. I emphasize that, despite their nature as historic documents, secret police files have uncanny relevance for understanding the present-day societies of mass surveillance.