This paper explores task evolution in English for Academic Purposes (EAP) writing materials, taking, as an illustrative case, written commentaries on non-verbal material such as that found in tables or graphs. The choice of this family of tasks is motivated by the fact that they have regularly occurred in EAP and English for Science and Technology (EST) textbooks from their outset in the 1970s and continue to be incorporated up to the present, as in Caplan & Johns (2022). We trace, with illustrative tasks and written responses, the evolution from Information Transfer (Widdowson, 1979) to Data Commentary, and on to Critical Commentary. We argue that this microcosm of EAP writing materials has, in fact, important parallels with other, more demanding, part genres such as reviews of the literature (from paraphrasing, to consolidating, and on to critical appraisal). We recognize that, in comparison to Second Language Acquisition (SLA) and Task-based Language Teaching (TBLT), the concept of “task” in EAP has been seriously undertheorized, and in the opening and closing sections, we attempt to rectify this.