The paper addresses the cognitive and functional characteristics of widely used, albeit insufficiently investigated Not that clauses in Modern English fiction and corpora. Functionally, the structure is shown to play a salient part in discourse structuring, as well as topic shift and development. Cognitively, it prevents the reader’s possible misinterpretation of the narrator’s intent, reveals the narrator’s voice and allows making inferences about the narrator’s and the characters’ attitudes and perspectives.