Perceptions, thoughts, pictures and expressions are all typically about something. In mental cases the relation is called intentionality, in pictures depiction, in expressions denotation. The nature of this aboutness has long been a topic for philosophical puzzlement and controversy. Whether it requires the existence of a kind of thing, quality or relation not found in inanimate nature, whether it is analysable, whether it comes in one or many forms, are all matters of dispute. The ontology of aboutness has to be at least plausibly conjectured if its features are to be represented within information systems that are sophisticated and capable enough to themselves represent representation. It falls therefore to the ontologist to investigate the entities and factors required and suitable to capture the form and matter of representation. This is no straightforward task, and there are many pitfalls. But it is a task that must be taken up if ontologies and the information systems that employ them are to advance to a stage where conjecture, diversity of opinion, (mis)information, uncertainty, falsehood, error, revision, contradiction and correction are to be smoothly represented and reconciled, and linked, as they must be, to action and decision, whether natural or artificial. Looking for help past and present, this paper sets about addressing that difficult task.